AuthenticationExtension.cs methods not run by SSRS

[r-coursera1]

I have an almost working implementation for forms authentication SSRS. The only issue is that none of the methods implemented by AuthenticationExtension.cs are getting called by SSRS

I tried to log it using Nlog but the interface functions (and the property) implemented in AuthenticationExtension.cs don't seem to get run by the SSRS !

public class AuthenticationExtension : IAuthenticationExtension2, IExtension
 {
 // .... other stuff

  Logger _logger;

public AuthenticationExtension()
{
   _logger = LogManager.GetCurrentClassLogger();
}

LocalizedName 
{ 
 get 
   {
    _logger.Info("LocalizedName"); 
    return null;
 } 
}

public bool LogonUser(string userName, string password, string authority)
{
    _logger.Info("LogonUser");
    return true;
}

public bool IsValidPrincipalName(string principalName)
{
  _logger.Info("IsValidPrincipalName");
  return true;
}

// other stuff
}

NLog logging works perfectly in Login.aspx.cs
But, no NLog logs for these 3 methods!

[r-coursera1]

As per https://github.com/microsoft/Reporting-Services/issues/237#issuecomment-1125958610, I attached my debugger to the running processes

ReportingServicesService.exe RSPortal.exe

but the breakpoints set at the beginning of LogonUser(),LocalizedName, IsValidPrincipalName() are still not hit.