GMX, WEB.DE and mail.com · permanent error
550: envelope domain on a GMX blocklist
GMX refused your mail because the domain in your envelope sender (MAIL FROM) is on one of its own blocklists.
- GMX, WEB.DE
- Provider
- Permanent (5xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 550
- Provider
- GMX, WEB.DE and mail.com
- Temporary or permanent
- PermanentRefused for good: the message comes back to the sender, and resending it gets the same answer.
- Who has to act
- The sender. The fix is on the sending side: your domain, your server or your list.
- What the server says
550 Reject due to policy restrictions
What it means
GMX keeps blocklists for domains as well as IPs. Case r1101 means the domain of your envelope sender, the address in MAIL FROM (RFC 5321), is listed, so GMX rejects the mail with 550 whatever server it comes from. The list is internal, so public blocklist checks will not show it. GMX asks you to stop the misuse that led to the listing, then contact it through the form on the case page and name the MAIL FROM domain you use, which it needs to process the request.
Common causes
- Spam was sent with your domain as the envelope sender, by you or by someone abusing it.
- A bulk sending service used your domain for traffic GMX judged to be abuse.
- The domain was previously used by someone else and kept a listing.
How to fix it
- 01Find out which systems send with your domain in the MAIL FROM and stop any misuse.
- 02Publish SPF, DKIM and DMARC so others cannot easily send under your domain.
- 03Contact GMX through the case page form and state the MAIL FROM domain you use.
Sources
What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.
- GMX Postmaster case r1101: 550 Reject due to policy restrictionspostmaster.gmx.net
Related codes
- 550Sender domain on a Spamhaus blocklist.GMX refused your mail because your envelope or From domain is listed on a Spamhaus blocklist. GMX makes no exceptions; the listing must be removed at Spamhaus.
- 554IP address on the GMX blocklist.Your sending IP is on a blocklist that GMX manages itself, so its servers refuse the connection. GMX keeps a strict no tolerance policy toward spam.
- 550Mailbox unavailable.The receiving server permanently refused the message for this recipient: the mailbox does not exist, cannot be reached, or the server rejected the message by policy.
550 at other providers
- 550 [SC-001]Outlook.com policy block for content or reputation.Outlook.com rejected the mail for policy reasons tied to spam-like content or to the reputation of the sending IP or domain.
- 550 [SC-002]Outlook.com block for namespace mining.Outlook.com blocked the sending IP because it behaved like a namespace miner, checking whether addresses exist without sending mail.
- 550 [SC-003]Outlook.com block for an open proxy or relay.Outlook.com rejected the mail because the sending IP appears to be an open proxy or open relay.
- 550 [SC-004]Outlook.com block after complaints.Outlook.com placed a block on the sending IP because it received complaints about mail coming from it.
- 550 [DY-001]Outlook.com refuses dynamic IP addresses.Outlook.com rejected the mail because the sending IP is dynamic address space, which it generally does not accept mail from.
- 550 [DY-002]Outlook.com block for a likely compromised sender.Outlook.com rejected the mail because the sending server or computer appears to be compromised or infected.
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