Ran into a problem with Exchange 2013 CU23, after updating OWA was unavailable. Users could login, but after doing so got an "Something went wrong" message.
Turns out the Exchange Server Auth Certificate got pointed to the wrong certificate. To solve this issue:
Find out what Exchange is using for the current auth certificate by running the following command:
Get-ExchangeCertificate (Get-AuthConfig).CurrentCertificateThumbprintIf you get an error running the command above, it means that the patch changed your auth certificate. You need to point exchange back to the correct certificate. To do that, you need to find the thumbprint of the auth certificate on your server. You can do this by running the following command:
Get-ExchangeCertificate
Look for the auth certificate on your exchange server and get the thumbprint of that certificate. Output of the Get-ExchangeCertificate follows:
Thumbprint Subject
7F7B8143A318C4E93796099E53D9D748F2FE0xxx CN=Microsoft Exchange Server Auth Certificate
As other posters have mentioned, to point Exchange back to the correct certificate, run the following commands:
Set-AuthConfig -NewCertificateThumbprint 7F7B8143A318C4E93796099E53D9D748F2FE0xxx -NewCertificateEffectiveDate (Get-Date)
Set-AuthConfig -PublishCertificate
Set-AuthConfig -ClearPreviousCertificate
(copy-pasted from here).
In my case, doing the above and restarting IIS worked.
