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Mailgun: Email Delivery Failures to Microsoft 365 Domains

No impact listedStatus: resolvedStarted Resolved (0 min)1 updatestspg.io (opens in new tab)

Affected components: Email Services - Outbound DeliveryOutbound Delivery

Timeline of updates

  1. resolved

    We have received confirmation that an external issue impacting email delivery to Microsoft 365 domains has been resolved. Impacted messages would have received an error stating "5.7.511 Access denied, banned sender" between Friday, August 14th and Monday, August 17th. Any failed messages will need to be resent.

    Information on retrying messages can be found in our Help Center here: https://help.mailgun.com/hc/en-us/articles/18596982041883-Resending-messages (opens in new tab)

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Impact, status and times are the vendor’s own, as last archived. View on stspg.io (opens in new tab).

Cite this

Status incident (vendor impact label: none) posted by Mailgun, started 2026-08-17 20:18 UTC, resolved after 0 min, 1 update(s).

Title
Email Delivery Failures to Microsoft 365 Domains
Vendor
Mailgun
Date
URL
https://rewindex.com/company/mailgun/incidents/vwhk7lx3lvs3

Mailgun profileRecent Mailgun incidentsAll outages on August 17, 2026Mailgun in August 2026MarkdownJSON