We have a brand-new server running Windows Server 2012, IIS 8, and MS SQL 2014. We have tested the forums and our custom integration successfully on a windows 10 machine running the same version of MS SQL and IIS 10. We've performed the installation successfully with the stock forums on the new machine.
The forums will load, but when we try to log in, it appears to authorize the credentials, but then we are presented with the "you must login or register" message again. There are no errors in the event log, nor in the IIS application, nor in the IIS logs.
We downloaded the source code, applied our config files, and ran it in Visual Studio on it's built-in IIS Express, and the login functionality worked exactly as expected. We performed a fresh compile from this working code, published it to the new site, and we experience the same issue where authentication succeeds but reverts to logged out condition.
We have tried changing the redirect on login as per several posts found here, but to no avail - the results are the same. We are now at our wits' end. Please help.