5.7.508 Microsoft bounce: ipv6 range over limit
What 5.7.508 means
The sender's IPv6 range sent too many messages in too short a time, so Exchange Online refused the traffic.
Message text
Access denied, [sender IP] has exceeded permitted limits within [range] range
Common causes of 5.7.508
- IPv6 range sent a burst of messages above permitted limits
How to fix 5.7.508
- Slow down sending from that IPv6 range and retry later.
- Check the sending addresses with blocklist check.
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How to read 5.7.508
The second part, 5.7.508, is an enhanced status code (RFC 3463 §2) written class.subject.detail. Class 5 is a Permanent failure (5xx): the command was rejected and the sender should not repeat it unchanged (RFC 5321 §4.2.1; RFC 3463 §2).. Subject 7 is security or policy: authentication, authorization or policy refused the message. The detail number refines the subject, and providers may define details of their own, which is why one code can read differently at Gmail, Microsoft and Yahoo.
Do not keep resending the same message: a permanent failure repeats until the cause is fixed. Correct the cause, then send a new message.
Official source: learn.microsoft.com. Last verified 2026-10-20.
Related guides
- How to create an SPF record (syntax and examples)
- How DKIM works and how to publish a DKIM record
- How to set up a DMARC record, from p=none to p=reject
Related codes
- 5.7.0 SMTP: security status
- 5.7.1 SMTP: delivery not authorized
- 5.7.23 SMTP: SPF validation failed
- 5.7.25 SMTP: reverse DNS failed
- 5.7.26 SMTP: authentication failed
- 5.7.27 SMTP: sender has null MX
FAQ
What does 5.7.508 mean?
The sender's IPv6 range sent too many messages in too short a time, so Exchange Online refused the traffic. This is a permanent failure.
How do I fix 5.7.508?
Slow down sending from that IPv6 range and retry later. Check the sending addresses with blocklist check.
Is 5.7.508 permanent, and should I retry?
5.7.508 is a permanent failure, so retrying the same message will fail again. Fix the cause first, then send a new message.