I figured it out, it was self inflicted. The trustworthy option got set to Off when i was trying to create a CLR stored procedure. Setting the Trustworthy to On...

Try this link
https://social.msdn.microsoft.com/Forums/en-US/c3e11282-495b-4e2a-b422-524dba378444/custom-authentication-provider-for-ssrs-2016-?forum=SQLServer2016Preview#65c40d6e-9ce6-4b8d-a27b-0bd9ec3d46f4

Look at the accepted answer. We were able to get it working but then had issues with the report builder and being able to...