azure email communication service mail not sending

Amith Chavan R 0 Reputation points
2026-11-13T09:35:56.4166667+00:00

Using the Azure portal’s Try Email (no custom code), sends are accepted but the operation stays Running with error: null indefinitely. No 429, domain fully verified. Operation ID: f653e97d-7827-4737-a152-13ecb70eb4df (design-dev-acs, UK). Last successful

Azure Communication Services
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  1. TP 165.6K Reputation points Volunteer Moderator
    2026-11-13T13:50:28.7233333+00:00

    Hi,

    It is likely your email delivery problem is due to the current major Microsoft 365 outage. ACS uses same sending infrastructure as M365/Exchange Online in my experience, and people started having issues around the same time the outage began.

    I performed quick test at about 2026-11-13 01:43 UTC by sending test email from ACS to one of my email servers, and the test email just arrived about 30 minutes ago. My test email server did not receive any connections from MS outbound servers during all of these hours. Typically, after clicking send in ACS an outbound server will connect to my server within seconds.

    I believe once Microsoft 365 outage is fully resolved your ACS sending will function as normal. Please check Microsoft Service Health Status page for updates using link below:

    https://status.cloud.microsoft/

    Please click Accept Answer and upvote if the above was helpful.

    Thanks.

    -TP

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