Update November 10, 2026: This blog post has been updated to reflect that the solution for issues mentioned is to install November 2026 (or later) updates for Windows Server that your Exchange Server...
Updated Nov 10, 2026
Version 4.0
Blog Post
2 MIN READ
Exchange servers may become unstable after installation of October 2026 Windows updates
I had problems with Outlook on mobile last week Monday and this week Monday again. And we use Exchange Online here. So, not sure if related (there are on prem servers as well, but my mailbox is in the cloud). But i didn't notice issues the other days. When it was happening it would take very long to refresh Inbox, it would show new emails along with already deleted.
Nino_Bilic
Microsoft
MicrosoftIf there was some sort of service issue, this could impact on-premises users who use Outlook Mobile because Outlook Mobile is a cloud-backed application. Using Basic authentication with Outlook for iOS and Android | Microsoft Learn.