Microsoft has released security updates for vulnerabilities found in:
Exchange Server 2013
Exchange Server 2016
Exchange Server 2019
These updates are available for the following specific...
Updated Jan 12, 2022
Version 17.0
Blog Post
Brent-H : We are having the exact same issue now Anyone have a solution or pointer for resolving this?
I'm also seeing hybrid users (mailbox in 365) that log in to on-prem Exchange OWA (and normally get a redirect "Use the following link to open this mailbox with the best performance") are now getting "We can't get that information right now. Please try again later.". The issue seems to be the character encoding in the URL, for example:
https://mail.example.com/owa/auth/errorFE.aspx?redirectType=Manual\u0026extDomain=example.onmicrosoft.com\u0026extDirOrgId=\u0026extEmail=someone%40example.mail.onmicrosoft.com
contains "\u0026" instead of "&". (u0026 is the Unicode for ampersand). When I change the slash u0026 to "&" manually in the browser (Chrome or Firefox)'s address bar, it displays the normal "Use the following link to open this mailbox with the best performance:" redirect message. The redirect is coming from /owa/auth.owa according to Chrome's devtools. A local mailbox account could log in fine.