Email Settings GuideQuick answer: STRATO uses one set of mail servers for every mailbox. Incoming IMAP runs on imap.strato.de over 993. POP3 uses pop3.strato.de over 995 and outgoing SMTP uses smtp.strato.de over 465, each secured with SSL. Sign in with the full email address and the STRATO mailbox password you manage in the customer login. Find your exact values in the E-Mail area of your account. For sending, STRATO wants 465 with SSL not 587.
What Changed Recently#
STRATO renames its webmail more often than it changes the server addresses. Here is where things stand today for STRATO mail and what it means for your setup.
Worth knowing
The webmailer was renamed. The browser mail STRATO used to call Communicator is now STRATO Webmail, built on Open-Xchange. It lives at webmail.strato.com. Your imap.strato.de client settings did not change.
Worth knowing
POP3 uses pop3.strato.de with the number three. Typing pop.strato.de out of habit fails. IMAP and SMTP drop the number, so imap.strato.de and smtp.strato.de are the right hosts.
Worth knowing
Your password lives in the customer login. The STRATO mailbox password is set in the STRATO customer login, not in the webmailer. The webmailer has no forgot password link, so reset the password at strato.de instead.
Before You Begin#
Handle these two basics before anything else. Skip them and your email app will reject the connection even when every server value is correct.
1. Create the mailbox
Add the address in the STRATO customer login under E-Mail and set its password. STRATO mail clients sign in with exactly that password.
Where: STRATO customer login then E-Mail
2. Note your servers
STRATO mail runs on imap.strato.de for IMAP and smtp.strato.de for SMTP. POP3 sits on pop3.strato.de with the number three.
Where: Find your settings →
About STRATO Mail#
STRATO is a German hosting provider founded in 1997 and based in Berlin. It is part of the United Internet group. STRATO email runs on its own servers rather than a per domain hostname.
STRATO has offered hosting, domains and email since 1997 and serves customers across Germany and other European markets. For email the point to remember is that every mailbox uses the same servers, imap.strato.de for incoming and smtp.strato.de for outgoing, with pop3.strato.de as the POP option. You sign in with the whole address and your STRATO mailbox password. STRATO keeps mail on its own servers in Germany under German data rules.
| Service Name | STRATO Email |
| Mail System | STRATO mail servers |
| Owned By | STRATO AG (United Internet) |
| Founded | 1997 |
| Based In | Berlin, Germany |
| Email Type | Custom domains, such as you@yourdomain.com |
| Webmail URL | webmail.strato.com |
| Webmail Name | STRATO Webmail (formerly Communicator) |
| Protocols Supported | IMAP, POP3, SMTP |
| App Password Needed | No, mailbox password |
| Username | Full email address |
STRATO Webmail Login#
You can always read your mail in a browser. The official STRATO pages are:
Find Your Settings#
A STRATO mailbox has IMAP on from the start, so there is nothing to enable. To confirm the values for one address, open the STRATO customer login.
- Sign in to the STRATO customer login at strato.de.
- Open the E-Mail area and pick the mailbox you want.
- Set or reset the mailbox password there if you need to.
- Use imap.strato.de and smtp.strato.de over SSL in your app.
STRATO IMAP Settings#
IMAP is the incoming choice STRATO recommends. STRATO keeps mail on the server, so a laptop and a phone share one inbox. STRATO also supports IMAP IDLE, so new mail appears without a manual refresh.
| IMAP Server | imap.strato.de | |
| Port | 993 | |
| Encryption | SSL/TLS (required) | |
| Username | Your full email address, including @yourdomain.com | |
| Password | Your mailbox password | |
| Authentication | Required |
STRATO POP3 Settings#
POP3 downloads mail to 1 device. Pick it only if you want a local copy on a single computer. Not sure? See the comparison below.
| POP3 Server | pop3.strato.de | |
| Port | 995 | |
| Encryption | SSL/TLS (required) | |
| Username | Your full email address | |
| Password | Your mailbox password |
STRATO SMTP Settings#
SMTP handles outgoing mail. If you can read mail but not send it, the problem is here.
| SMTP Server | smtp.strato.de | |
| Port | 465 | |
| Encryption | SSL/TLS (required) | |
| Username | Your full email address | |
| Password | Same as incoming mail | |
| Authentication | Required. Switch on outgoing server authentication in the client. |
465 with SSL. Many home connections block port 25. For a normal mail app 465 with SSL is the only STRATO SMTP port. STRATO keeps 587 and 25 STARTTLS for server relay setups, not email clients. Confirm outgoing authentication is on.
Check STRATO IMAP Settings Online#
You don't need to download anything to check STRATO IMAP settings online. This page is the lookup: every value is verified, current and copyable straight from your browser. Not sure your address uses STRATO servers? Enter it below to check in a moment.
Does my email address use these settings?
Runs in your browser only. Your address is never sent anywhere or stored.
Want to verify the account itself before configuring an app? Sign in at STRATO Webmail, which confirms your address and password work. If webmail opens, any email app connects with the tables above.
Look Up IMAP Settings for Any Email Domain#
This page covers STRATO. For every other address, work email on a company domain included, we run a free online lookup database: imapsettings.com.
imapsettings.com
Complete email settings database, by Univik
Enter any email address and get the incoming and outgoing server settings for that domain in 1 step:
Your address is used only to find the settings for that domain. Nothing is stored or shared.
Username and Password#
Both come from the mailbox itself. The username is the whole email address and the password is the one you set for that mailbox in the STRATO customer login. A STRATO mailbox uses no app password.
Username is the full address
Type you@yourdomain.com in full, with the part after the at sign. STRATO turns down a bare mailbox name.
Put that same address on both incoming and outgoing.
Password is the mailbox one
This is the mailbox password you set in the STRATO customer login, not your customer account password. The webmailer itself has no reset link, so change it at strato.de.
The two factor prompt on the STRATO customer login guards your account, not the mailbox connection.
Set Up STRATO in Email Clients#
The servers and ports are always the same. Only the menus differ. Jump to your app:
Outlook (Windows and Mac)
- In Outlook select Add Account, then turn on manual setup under Advanced options.
- Choose IMAP and set incoming to
imap.strato.deon 993 with SSL. - Set outgoing to
smtp.strato.deon 465 with SSL. - Enter the full address and mailbox password when Outlook prompts you.
- Send a test message to yourself to prove both paths.
Apple Mail (macOS)
- In Mail select Add Account, then pick Other Mail Account.
- Give your name, STRATO address and password, then continue.
- Enter imap.strato.de for incoming and smtp.strato.de for outgoing, both with SSL.
- Keep the SSL ports so nothing sends in plain text.
- Save and wait for the mailbox to load.
iPhone and iPad
- In Settings open Mail, then tap Mail Accounts and Add Account.
- Tap Other then Add Mail Account and fill your details.
- Keep IMAP chosen and put imap.strato.de for incoming and smtp.strato.de for outgoing.
- Leave the secure ports iOS fills, since STRATO expects SSL.
- Tap Save and let iOS run its check.
Android
- Open your mail app and tap Add account, then Other or IMAP.
- Put in your address and password. Switch to manual setup if it stalls.
- For incoming use imap.strato.de on 993 over SSL.
- For outgoing use smtp.strato.de on 465 over SSL.
- Save and swipe down to fetch your mail.
Thunderbird
- In Thunderbird pick Account Actions, then Add Mail Account.
- Type your name, STRATO address and password, then Continue.
- Wait for detection, then make sure IMAP with SSL is picked.
- If detection fails, type imap.strato.de for incoming and smtp.strato.de for outgoing.
- Hit Done and the folders fill in on the first sync.
STRATO Webmail Settings#
Server settings connect your apps. These settings decide how a STRATO mailbox behaves on the server. They live in STRATO Webmail at webmail.strato.com, the Open-Xchange browser mail STRATO used to call Communicator.
Signature
Add one in STRATO Webmail preferences. The signature rides on messages sent from the browser. A desktop app keeps a signature of its own.
Vacation Auto Reply
Set an out of office reply in STRATO Webmail and give it start and end dates. The STRATO server sends it, so it fires even when your machine is off.
Filters and Folders
Create filters in STRATO Webmail. A server side rule sorts a message ahead of any device fetching it. A rule set inside an app only works while that app is running.
Spam and Blocked Senders
STRATO filters incoming mail for spam. Manage rules and blocked senders in STRATO Webmail. Flagged mail lands in the junk folder for a look.
POP3 vs IMAP#
| Feature | IMAP | POP3 |
|---|---|---|
| Where mail lives | On the STRATO server | Downloaded to 1 device |
| Multiple devices | ✅ Everything stays in sync | ❌ Each device sees different mail |
| Sent and deleted mail | ✅ Synced everywhere | ⚠️ Stays only on that device |
| Offline reading | ⚠️ Cached mail only | ✅ Full local copy |
| Server storage used | Yes, counts against your quota | Can be freed after download |
| Best for | Phone + computer, everyday use | Single PC, local archives |
STRATO Sending and Storage Limits#
A few limits are worth knowing before you bulk forward or move a mailbox. STRATO applies fair use limits on outbound mail to protect its servers:
| Outbound cap | Fair use limit on outbound mail |
| Username | Full email address |
| SMTP port | 465 with SSL for mail apps |
| Mailbox storage | Set by your STRATO package |
| Recycle bin | Deleted mail counts until you empty it |
| SMTP authentication | Required on smtp.strato.de |
Troubleshooting STRATO Connections#
Find the exact error your email app shows, then apply the fix:
| Error you see | What it means | Fix |
|---|---|---|
| Username or password rejected | Short username or wrong password | Use the full email address with the mailbox password from the STRATO customer login, not the customer account password. |
| Cannot send on port 25 | ISP blocks the default SMTP port | Switch outgoing to 465 with SSL. STRATO uses 587 and 25 STARTTLS for server relay only, so keep mail apps on 465. |
| POP3 host not found | pop.strato.de was typed by habit | POP3 sits on pop3.strato.de with the number three. IMAP and SMTP drop it, so imap.strato.de and smtp.strato.de are correct. |
| No reset link in webmail | Password is managed elsewhere | STRATO Webmail has no reset link. Change the mailbox password in the STRATO customer login at strato.de. |
| Cannot connect to server | Wrong port or encryption | Set 993 with SSL incoming and 465 with SSL outgoing. A firewall on your own machine can block it as well. |
| Repeated password prompt | Short username or a typo | Clear the saved login, then put in the full address with the mailbox password. |
| Messages stuck in Outbox | SMTP authentication is off | Enable "outgoing server requires authentication" with the same login as incoming mail. |
| Outgoing mail fails on 587 | 587 is a relay port | Switch the outbox to smtp.strato.de on 465 with SSL. STRATO keeps 587 and 25 STARTTLS for server relay, not mail apps. |
| SMTP login not accepted | Wrong authentication method | Set the authentication to normal password. STRATO does not support CRAM-MD5, so a client set to it is turned away. |
Reader Reported Fixes
Use the STRATO hosts. When a manual setup will not connect, enter imap.strato.de for IMAP, smtp.strato.de for sending and pop3.strato.de for POP3. Those carry the STRATO certificate and clear the guesswork behind most failed setups.
Test the login in webmail first. Sign in at webmail.strato.com with the full address and mailbox password. If webmail.strato.com opens, the login is right and the fault sits in the app settings.
Which SMTP Port and Login Does STRATO Use?#
Most guides list port 465 and stop there. STRATO adds two rules that trip people up. Get them right and outgoing mail sends the first time.
Use these in a mail app
- Server
smtp.strato.deon port465 - SSL/TLS on, full email address as username
- Authentication set to normal password
- Outgoing server authentication switched on
Leave these alone
- Ports 587 and 25 are server relay ports
- STARTTLS on 587 is for smarthost setups
- CRAM-MD5 is not supported by STRATO
Moving Mail In or Out?#
STRATO mail speaks plain IMAP, so a mailbox moves in or out like any standard account. On a STRATO move each folder stays on the server until the copy completes.
Take a copy first. Back up the mailbox before a move. Mail that arrives during a STRATO switch can land on either provider. A copy keeps you safe.
Carrying mail across? The Univik Email Migration Tool moves each folder over an IMAP link. Give it imap.strato.de with the mailbox password on this side and the other account opposite.
Rather hand it off? Our Email Migration Services team runs the whole move and verifies each folder arrived.
Use These Settings in Univik Email Backup#
The same IMAP settings above let you download your complete STRATO mailbox to your computer. Univik Email Backup saves everything as PST, MBOX, EML or PDF files you keep forever, even if the account closes.
- Download Univik Email Backup and install it on Windows.
- Select STRATO from the source list. If STRATO is not on the source list, pick a plain IMAP account.
- Give the complete email address with your mailbox password. The login name is always the whole email address.
- When the backup tool wants server details, hand it imap.strato.de on port 993 with SSL. Take those values straight from the IMAP table above, with port
993over SSL. - Pick a saving format and folder, then start the backup. Large mailboxes download in the background.
Univik Tools That Use These Settings#
Many people land here while migrating or archiving a mailbox. All 3 tools use the same IMAP settings from this page:
Email Backup
Download your complete STRATO mailbox to PST, MBOX, EML or PDF before switching or closing the account.
Email Backup Tool →
Email Migration Tool
Copy every folder from STRATO straight into Gmail, Microsoft 365 or any other account. No manual export needed.
Email Migration Tool →
Email Converter Tool
Already have MBOX, EML or OST files from an old export? Convert them to PST, PDF or any format your new app opens.
Email Converter Tool →Prefer to hand the whole migration to experts?
If the hostnames and passwords feel like busywork, you can let the tool handle it. Univik's migration team handles the complete project: planning, transfer, verification and a report showing every folder made it. Since 2013, for single mailboxes up to full company moves.
Email Settings Glossary#
IMAP
Internet Message Access Protocol. Reads mail that stays on the server, so all your devices see the same inbox, folders and read status.
POP3
Post Office Protocol version 3. Downloads mail to 1 device and can remove it from the server. Older method, still useful for local archives.
SMTP
Simple Mail Transfer Protocol. Sends your outgoing mail. Every account needs it next to IMAP or POP3, which only receive.
SSL / TLS / STARTTLS
Encryption for the connection. SSL/TLS encrypts from the start (ports 993, 995, 465). STARTTLS upgrades a plain connection (port 587).
Mailbox Password
The password you set for a STRATO address in the customer login. Your email apps use this, not your STRATO account password.
STRATO Webmail
STRATO browser mail at webmail.strato.com, built on Open-Xchange. It was called Communicator until recently.
STRATO Customer Login
The strato.de area where you create mailboxes, set passwords and manage your STRATO products.
STRATO Communicator
The former name of STRATO Webmail. Older guides and bookmarks still use it for the same browser mail.
IMAP IDLE
A push feature STRATO supports, so new mail appears in your app without a manual refresh.
imap.strato.de
The STRATO incoming server for IMAP on port 993 over SSL. POP3 uses pop3.strato.de instead.
smtp.strato.de
The STRATO outbox server for sending on port 465 over SSL. For mail apps 465 is the only port. 587 STARTTLS is for server relay.
Kundenlogin
The German name for the STRATO customer login where mailbox passwords and settings live.
pop3.strato.de
The STRATO POP3 server on port 995 over SSL. Note the number three, since pop.strato.de does not exist.
Open-Xchange App Suite
The webmail platform behind STRATO Webmail. It runs in the browser at webmail.strato.com with no install.
SMTP Authentication
The outgoing login STRATO requires. Set it to normal password, since STRATO does not support CRAM-MD5.
How We Verify These Settings#
Univik builds email backup, migration and converter software since 2013. Our tools sign in to STRATO over IMAP and SMTP every day for thousands of users, so a changed server, port or login rule shows up in our connection logs before most guides notice it.
Every value on this page is confirmed with three checks: a live IMAP and SMTP connection from Univik Email Backup, a comparison against the STRATO guides and a sign in with a real mailbox using the full address. We re verify after any provider announcement and at least once a quarter.
Found something that no longer matches what STRATO shows you? Tell us and we will retest and update the page, with the change logged in what changed recently.
Help & Support
Frequently Asked Questions
Point your app at imap.strato.de on port 993 over SSL. Your login name is the full email address and the password is the mailbox password from the STRATO customer login. The IMAP settings section holds the full table.
Check the username first. It must be the complete address rather than the part before the at sign. A STRATO mailbox uses the mailbox password with no app password. The two factor prompt on the customer login does not affect the mailbox.
IMAP suits nearly everyone and STRATO recommends it. Mail stays on the server so every device matches. POP3 on pop3.strato.de pulls mail down to one machine and can lose it if that machine fails. Full comparison here.
Yes. The server, ports and encryption match on iPhone, Android and Windows. Only the path to the settings screen shifts by app, which the client setup guides spell out.
STRATO Webmail has no reset link by design. The mailbox password is managed in the STRATO customer login at strato.de. Open the E-Mail area, pick the address and set a new password there.
Yes. Leave SSL set on each server so the sign in never travels in the open. Set a strong mailbox password in the customer login. Turn on two factor sign in for the STRATO customer login to guard your account.
An email client with IMAP downloads mail as it syncs, but a dedicated backup tool is faster and saves standard files you can open anywhere. See how to back up your STRATO mailbox. If you already exported files in another format, an email converter changes them to PST, PDF or whatever your new app opens.
With STRATO mail the culprit is normally a short username, a bad password or a blocked port. Check what to know. Enter the whole address with the mailbox password, then 993 incoming and 465 outgoing over SSL.
A migration tool copies mail across the two accounts on an IMAP link. Give the STRATO IMAP settings with the mailbox password on this side and the destination details on the other. Each folder lands with its dates intact.
If setting this up feels risky or you have many accounts to move, our managed email migration service does the entire job for you.
No. STRATO offers no dedicated mail app. Set your STRATO mailbox up in any mail app with the IMAP settings, using imap.strato.de for incoming and smtp.strato.de for sending over SSL.
Other Email Provider Settings
Summary: STRATO Settings at a Glance
- IMAP: imap.strato.de, port 993, SSL/TLS
- POP3: pop3.strato.de, port 995, SSL/TLS
- SMTP: smtp.strato.de, port 465, SSL/TLS
- Username is always your full email address
- STRATO mailbox on STRATO servers
- Pick IMAP for phone + computer sync
- Full address as the username
- Username is always the full email address