Major incident

Fasthosts: Sending email to Microsoft-hosted email addresses may not be possible

Affected: Sending Mail

Current status of Fasthosts: Operational — live Fasthosts status

Timeline

1. Jun 30, 2026, 10:51 UTC
   identified
   Some emails sent to Microsoft-hosted email addresses may be rejected due to Microsoft blocking some of our IP addresses. We are in contact with Microsoft to request de-listing. Please accept our apologies for any inconvenience you may be experiencing.
2. Jun 30, 2026, 13:04 UTC
   identified
   We have eliminated the disruption for some of those affected.
3. Jun 30, 2026, 17:09 UTC
   monitoring
   The affected IP address has been unblocked. Now that service has been restored and the IP address's reputation is being re-established, it may take up to 24–48 hours for the change to fully propagate across our systems. During this time, some email sending limits may still remain in effect. Thank you for your patience and understanding.
4. Jul 2, 2026, 06:41 UTC
   monitoring
   We are still working on resolving this issue. Our apologies for the inconvenience caused.
5. Jul 2, 2026, 13:43 UTC
   identified
   We have found the cause for the disruption and are working on resolving it.
6. Jul 3, 2026, 07:10 UTC
   identified
   Microsoft has confirmed mitigations on their side, but we're still seeing blocks. These happen when Microsoft detects traffic it considers higher than expected and applies restrictions outside of our control. Our engineering team is actively working to optimise mail flows and reduce the chance of these blocks. We're in regular contact with Microsoft to push for a lasting fix, and this remains a top priority.
7. Jul 6, 2026, 10:51 UTC
   monitoring
   We have eliminated the disruption for almost everyone affected.
8. Jul 6, 2026, 12:17 UTC
   resolved
   This incident has been resolved.

Updates as published by Fasthosts (original).