Few days back I was on one of the implementation of Exchange Server 2016. My Team has successfully installed the exchange server 2016 and health checkup was good on EMS using Test-Servicehealth. But when we tried to open the OWA or ECP page we got stuck with the error ‘X-OWA-Error Microsoft.Exchange.Diagnostics.ExAssertException‘. This means we were getting ExAssertException issue on Exchange OWA and ECP page. Let’s work on how I resolved this issue.
I checked everything reset the OWAapplicationPool but still the issue was same… no change on the issue. Then going through the forum, I found that this might be the certificate issue. Hence started to work on the default certificates of the exchange server.
As said earlier, I worked on the Exchange default certificate to resolve this issue. The best way to resolve this issue was to create a new Exchange Certificate. Hence, I create a new certificate with below cmdlet on EMS (Exchange Management Shell)
New-ExchangeCertificate -KeySize 2048 -PrivateKeyExportable $true -SubjectName "cn=Microsoft Exchange Server Auth Certificate" -FriendlyName "Microsoft Exchange Server Auth Certificate" -DomainName "pdhewaju.com.np"
There prompts to replace the SMTP Certificate on which type ‘N’.
After creating the certificate, now run the updatecas.ps1 and updateConfigfile.ps1. The PS scripts are available on the location:
C:\Program Files\Microsoft\Exchange Server\V15\Bin\
Hope this helps you to resolve your issue with ExAssertException on Exchange OWA/ECP. Please leave comment if issue still persist.