Hello,
it is strange.
What are the application pool settings in IIS? Are you using Integrated or Classic pipeline mode? If you are using classic, could you please try to switch it to integrated?
What version of IIS do you use?
Have you followed the "new approach" settings -
Custom URL extensions?
Do you use the Windows authentication or the Forms authentication?
How does it behave? Do you type in the credentials, you are redirected to the site and there is no current user?
Thank you in advance for your response.
Best regards,
Helena Grulichova