Microsoft has been having a tough month for sure. The company was forced to release multiple emergency OOB patches to fix major issues, including the latest one under KB5085516 that resolves a sign-in bug which wouldn"t let users connect to the internet and use the free Microsoft Windows 11 apps.
On the Microsoft 365 front too it has not been flawless, as the company recently had a big outage wherein Office.com was not accessible for long hours, potentially as a consequence of an Exchange Online mailbox issue.
That happened exactly one week ago, and just a few days later, on the 20th, the company confirmed another issue wherein it noted that accessing Exchange Online services through the Outlook mobile apps or the New Outlook for Mac desktop client were getting disrupted. It wrote: "This issue may intermittently impact some users who are attempting to access the Exchange Online service through the Outlook Android mobile apps or the new Outlook for Mac desktop client."
At the time, Microsoft had offered a workaround which involved restarting or rebooting the device though it had acknowledged that it was hardly a proper fix as it said: "While we’ve previously identified that restarting the affected infrastructure isn’t a sufficient fix for this issue on a wide scale; we"ve confirmed that it does provide immediate temporary relief." The company however confirmed that it was "performing a deeper analysis into understanding the specifics of the root cause."
After further investigating the changes it made, Microsoft has confirmed today that the new update is indeed responsible for the issue, and as such, it has withdrawn it. The problem is due to the compatibility conflicts as a result of the introduction of a new virtual account. The company has updated the support article to add the following: "After further assessment, Microsoft has confirmed that the identified change within the Exchange Online service intended to introduce a new virtual account resulted in impact. To remediate this issue, they are disabling the change across the affected environments."
The issue, under EX1256020, is still open as Microsoft continues to look into the matter.