For IIS Windows Authentication, remove Negotiate and just keep NTLM. See if you have any better luck.
It then worked but then I changed it back and it still worked???!?!?!?!?!
This was the instructions
go to IIS manager
– expand, server, go to sites
– select the CRM website
– in the feature view, select Authentication
– select windows authentication
– click on Providers, and add negotiate as second enabled provider after NTLM.
The only thing I think I have done is move NTLM so it’s the process that it first tries. Either way it is now working and I am going to slowly back away from IIS Manager and the configuration settings