smpt server in GMX mail account

Question

Hi, I have a problem with smtp server in my Gmx-Mail account integrated in Outlook, i.e. cannot send any mails

Answer 1

Hello Richard Pearson, and thank you for posting to Microsoft Q&A. I understand how concerning it is when you cannot send emails through your GMX account in Outlook, and I appreciate you sharing your concern here. 

Based on the issue described, it appears the connection between Outlook and the GMX SMTP server is being blocked or misconfigured. Here are the steps to resolve this: 

Step 1: Re-enable External Access in GMX 

• Log into your GMX account via a web browser. 
• Go to Settings (or Email Settings). 
• Navigate to POP3 & IMAP. 
• Check the box for "Enable access to this account via POP3 and IMAP" and click Save. 

Step 2: Force SMTP Authentication in Outlook 

• Open Classic Outlook and go to File > Account Settings > Account Settings. 
• Double-click your GMX email address. 
• Click the More Settings... button. 
• Go to the Outgoing Server tab. 
• Check the box "My outgoing server (SMTP) requires authentication" and ensure "Use same settings as my incoming mail server" is selected. 

Step 3: Verify Port and Encryption Settings 

• Outgoing server (SMTP): mail.gmx.com (or mail.gmx.net if your email ends in .net) 
• Port: 587 
• Encryption Method: STARTTLS (or TLS) 
• (Alternative): If Port 587 fails, try Port 465 with SSL/TLS. 

I hope this information helps you resolve the sending issue. Please let me know if you need further assistance or if these steps worked for you. 

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Answer 2

The issue is typically caused by one of the following: incorrect SMTP settings, blocked SMTP connection, or the server not recognizing the account as authorized.

Try these steps in classic Outlook for Windows:

1. Verify GMX SMTP settings
   • Open Outlook.
   • Open the account settings for the GMX account.
   • Confirm the outgoing (SMTP) server name, port, encryption type, username, and password exactly as required by GMX.
   • Make sure the full email address and correct password are entered.
   • If GMX requires SSL/TLS or a non‑default port, ensure those are configured. If unsure, check GMX’s documentation for the correct SMTP server, port, and security settings.
2. Check for firewall/ISP blocking SMTP
   • If Outlook reports errors like “unable to connect to your outgoing (SMTP) e‑mail server” or timeouts, the ISP or network firewall may be blocking the SMTP port.
   • Contact the ISP or network administrator and ask if outbound SMTP to GMX’s server/port is blocked.
   • If they provide an alternative SMTP server or port, configure that in Outlook’s outgoing server settings for the GMX account.
3. Confirm credentials and authorization
   • If error codes like 550, 553, or “relay prohibited/relaying denied” appear, the GMX SMTP server is not recognizing the account as authorized.
   • Ensure “My outgoing server (SMTP) requires authentication” is enabled and that it uses the same credentials as the incoming server.
   • Make sure the “From”/reply address domain matches what GMX allows for sending; some providers reject messages if the reply address domain does not match the authenticated account.
4. Check for general Outlook send/receive issues
   • If Outlook shows generic send/receive errors (for example 0x80042109 or connection‑related codes), follow the standard Outlook troubleshooting for send/receive problems, including verifying server names, ports, and running the Inbox Repair Tool if data file corruption is suspected. See the error list and repair guidance in the referenced article.

If, after correcting SMTP settings and enabling SMTP authentication, messages still cannot be sent, contact GMX support with the exact error text from Outlook so they can confirm whether the account or IP is blocked or if additional settings are required.

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References:

• I can't send or receive messages with Outlook for Mac
• I receive a 550, 553, or relay-prohibited error when sending email messages
• I can't send or receive messages in Outlook