Status 1#
smtp;550 Requested action not taken: mailbox unavailable
The address does not exist, or is no longer active, at this provider. Remove it from your list and check for a typo in the local part or the domain.
Provider documentation
Email provider · 5.x.x permanent failure
GMX SMTP 550 Errors: Every Bounce Response Explained
Every SMTP 550 response on record from GMX, with the verbatim text, the enhanced status code, a severity rating and a plain-English fix.
The mailbox is unavailable and the message is rejected for good. This is the catch-all permanent failure, covering everything from an unknown address to an authentication failure to a reputation block, so the wording after the number is what actually tells you the reason.
- Provider
- GMX
- Code
- 550 (5xx)
- Responses
- 2
- Highest severity
- Unclassified
GMX SMTP 550 responses
Status 2#
Requested action not taken: mailbox unavailable Reject due to policy restrictions.
The address does not exist, or is no longer active, at this provider. Remove it from your list and check for a typo in the local part or the domain.
Provider documentation
Postmaster & documentation
GMX SMTP 550 questions
›What does an SMTP 550 error from GMX mean?
The mailbox is unavailable and the message is rejected for good. This is the catch-all permanent failure, covering everything from an unknown address to an authentication failure to a reputation block, so the wording after the number is what actually tells you the reason. At GMX, it is a permanent rejection, and the specific reason is in the enhanced status code and message text of each response below.
›How do I stop GMX from returning SMTP 550?
Match your bounce text to one of the responses below and follow its guidance. Recipient-side wording means fix the address. Authentication or reputation wording (SPF, DKIM, DMARC, blocklist) means fix your sending setup, and check GMX's postmaster documentation.