Update 4/15/2025: Updated the rollout schedule.
As with all cloud services, Exchange Online imposes service limits to prevent misuse of Exchange Online resources and ensure availability for all use...
Updated Apr 15, 2025
Version 15.0
Blog Post
Apparently one of our clients has been hit with this today. I've seen multiple mentions of exclaimer. I'm trying to get caught up as we were not aware of this change and now scrambling for a temporary solution...We have sev A ticket open but has anyone been through an outage yet and come up with a temporary work around?
Update:
- We purchased 800 exchange online plan 1 licenses to raise the threshold. The threshold was reflective of the new licenses in about 2 hours.
- We identified part of the issue is a custom application that developers had created a dummy email address but using our legitimate domain sending emails through send grid. This caused roughly 14K outbound NDR's through Exchange Online from the postmaster account in a 24-hour period.
We opened tickets with Microsoft and our distributor 12 hours ago and have not received a response.
Microsoft has stated they are unwilling to raise the thresholds even though NONE of their customers contractually agreed to this change in service.
Not sure this relates to your clients problems, but maybe my experience can help Introducing Exchange Online Tenant Outbound Email Limits | Microsoft Community Hub
might be able to just order more qualifying licenses to get you through the sliding window, then refund within the eligible window, assuming that you have already addressed the source generating the large number of outbound messages.
