I use a custom certificate with WAC and that causes this error in the Application log and the WAC service terminates:
Application: WindowsAdminCenter.exe
CoreCLR Version: 8.0.1024.46610
.NET Version: 8.0.10
Description: The process was terminated due to an unhandled exception.
Exception Info: System.InvalidOperationException: The requested certificate CN=servername.local could not be found in LocalMachine/My with AllowInvalid setting: False.
If I use the self-signed certificate the error is not present.
I figured out that what is causing the 'not found' error is that is it looking for the certificate without the X.500 prefix. Do the correct subject in the appsettings.json file should be just 'servername.local' and not 'CN=servername.local'. Once I made this change to my appsettings.json WAC started successfully with my custom certificate.