August 26, 2024 at 12:54PM
Microsoft is investigating a false positive issue in Exchange Online, where emails with images are wrongly tagged as malicious and quarantined. The ongoing service degradation issue seems widespread, affecting outbound traffic, replies, and forwards of external emails. This is reminiscent of a past issue in October 2023. Microsoft is actively working on a remediation plan.
Based on the meeting notes, the key takeaways are:
– Microsoft is currently investigating an Exchange Online false positive issue that is causing emails containing images to be incorrectly marked as malicious and sent to quarantine.
– The issue is being tracked under the reference EX873252 and is impacting both outbound traffic, specifically for replies and forwards of previously external emails, as well as messages with image signatures.
– System administrators have reported that the issue is widespread and is also impacting intra-organizational emails.
– Similar issues have been addressed by Microsoft in the past, such as the one in October 2023 caused by a bad anti-spam rule.
This is a developing issue that Microsoft is actively working on to isolate the root cause and develop a remediation plan.