ACS Email: sends accepted (202) but stuck in "Running" for hours, on two separate resources, no delivery status

wumb 20 Reputation points
2026-11-13T12:24:23.7166667+00:00

Problem
Since this morning (13 November 2026), emails sent through Azure Communication Services Email are accepted but not delivered. This happens on two independent Communication Services resources in the same subscription. Both use the Germany data location.

What happens

  • POST /emails:send?api-version=2025-09-01 (Python SDK azure-communication-email 1.1.0) returns 202 Accepted with an Operation-Location, as usual.
  • ACSEmailSendMailOperational logs the SendMail operation normally.
  • After that nothing happens. GET /emails/operations/{id} keeps returning "status": "Running" with "error": null. ACSEmailStatusUpdateOperational gets no OutForDelivery or Delivered entry.
  • Until 29 October, every email on both resources reached OutForDelivery and Delivered within seconds.

What I checked

  • Volume is tiny, at most a handful of emails per day, so no sending limits are anywhere near reached.
  • The custom domain's verification states are all Verified, and the Azure Managed Domain resource is affected the same way. That makes a domain or DNS cause unlikely.
  • Resource Health and Service Health show no active issue for the subscription.

Can someone from the ACS team look at the operation ID a8d86591-d457-432e-8b9c-82c0f388658c? It's the most important mail which is stuck.

The subscription is on a plan without technical support, so I can't open a support request. Thanks for any help.

Azure Communication Services
0 comments
Answer accepted by question author
TP 165.5K Reputation points Volunteer Moderator
2026-11-13T13:51:59.7166667+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

Was this answer helpful?

1 person found this answer helpful.

0 additional answers

Sort by: Most helpful
Most helpful Newest Oldest

Your answer

Answers can be marked as 'Accepted' by the question author and 'Recommended' by moderators, which helps users know the answer solved the author's problem.