GMX IMAP Settings

IMAP keeps your mail on GMX's servers and mirrors it to every device you connect. Read a message on your phone and it shows as read on your laptop; move it to a folder and the folder appears everywhere.

With GMX there is one step before any of that works, and it is the reason most setups fail on the first attempt.

First: switch IMAP access on

GMX deactivates POP3 and IMAP by default. Until you enable it, no mail program can connect — and the error you get is "authentication failed", which sends almost everyone re-checking a password that was never the problem.

1. Sign in to GMX in a browser.

2. Open the Email tab and click Settings.

3. Click POP3 & IMAP.

4. Tick Enable access to this account via POP3 and IMAP.

5. Click Save.

GMX's own IMAP documentation opens with this reminder, which tells you how often it is missed.

GMX may switch it off again later

Worth knowing before it happens: GMX turns this setting off automatically, for security reasons, if POP3 or IMAP goes unused for a long period.

So a setup that worked for months can simply stop, with nothing changed and no notification. If your mail program has suddenly started failing to authenticate and you changed nothing, check this switch first — re-ticking it is often the entire fix.

GMX IMAP settings

These cover incoming mail only. You will also need outgoing settings before you can send — our SMTP settings guide has those, and the combined settings guide has everything on one page.

German gmx.net accounts use imap.gmx.net instead. Same service, different servers, and using the wrong one fails in a way that looks exactly like wrong credentials.

Your program must support TLS 1.2 or 1.3

GMX no longer supports TLS 1.0 or 1.1. A mail program too old to speak the newer versions cannot connect at all — and it will report that as an authentication failure rather than a protocol problem, which is thoroughly misleading. If your software has not been updated in several years, this may be the whole story.

Adding the account

Open your program's account settings, choose to add an account, and pick the manual or advanced option rather than letting it guess. Automatic detection occasionally configures POP3 instead of IMAP — and POP downloads and removes server copies, which is a far worse problem than filling in a few fields yourself.

Outlook

Add the account, choose Let me set up my account manually under Advanced options, and select IMAP. Enter the settings above, then check More Settings → Outgoing Server and tick that the outgoing server requires authentication. Without it, mail arrives but never sends — and the failure looks unrelated to what you just configured.

Thunderbird

Enter your address and password, then confirm it has chosen IMAP with port 993 and SSL/TLS before finishing. Thunderbird is also a useful diagnostic: if another program has failed repeatedly and you are not sure why, Thunderbird tells you whether the problem is the account or the software.

Phone mail apps

GMX recommends its own Mail App for Android and iOS as the simpler route, and it needs none of this configuration. Use IMAP in a built-in mail app if you prefer that app — but the GMX app avoids both the enable switch and the app-password requirement.

After it connects

Fix the folder mapping

Many email programs cannot correctly match their own folders to GMX's system folders — a program's "Trash" may not line up with what GMX calls it — so the program creates its own instead, and your mailbox sprouts duplicates.

Set the mapping manually in your program's account settings so Sent, Drafts, Trash and Spam point at GMX's existing folders. Doing it once at setup avoids a mess that only gets harder to untangle.

Check your folder subscriptions

If mail is arriving in the GMX website but some folders never update in your program, subscriptions are the likely cause. Many IMAP clients only synchronise folders you have explicitly subscribed to, so a folder can exist and stay permanently empty on that device.

Most programs have a "manage subscriptions" or "folder subscriptions" option in the account settings.

Correct misfiled mail through GMX

GMX’s personal spam filter can be trained through GMX webmail and the official GMX Mail app. Marking a message as Spam or Not Spam through either of these official interfaces helps GMX classify future messages from that sender.

Moving a message between folders in a third-party mail program such as Outlook, Thunderbird or Apple Mail changes its location but does not train GMX’s spam filter. If a sender is repeatedly classified incorrectly, use Spam or Not Spam through GMX webmail or the official GMX Mail app.

If two-factor authentication is on

If two-factor authentication is enabled, use an application-specific password instead of your normal GMX password in the external mail program. Use that password wherever the program asks for the incoming account password. See our GMX Security guide for instructions on creating an application-specific password.

If it still will not connect

• Is IMAP access enabled? And has GMX switched it off since you last used it?

• Right hostname for your domain? gmx.com and gmx.net differ.

• Port 993 with SSL? Pairing it with STARTTLS fails even though both values look correct alone.

• Username is the full address? Not just the part before the @.

• App password, if 2FA is on?

• Does your program support TLS 1.2 or 1.3?

• Security software scanning mail? Antivirus and firewalls can block the connection silently.

And GMX's own best advice when an error makes no sense: sign in on the website on a computer. Some errors, such as temporary blocks, cannot be displayed properly by a mail program — the real message appears there with instructions.

If the program connects but mail is not arriving at all, that is a different problem. Our troubleshooting guide covers filter rules, the spam filter and storage.