I'm setting up a SharePoint 2016 site for a demo and discovered the pages don't display due to an HTTP 500 Internal Server Error. However Central Administration works just fine. Fortunately a Google search lead to this article from Cloudshare that contained the solution for me- https://www.cloudshare.com/blog/cloudshare/http-500-internal-server-error-explanation-how-to-fix It pertains to SP2013, but is exactly the same in SP2016. Basically the SecurityTokenServiceApplicationPool's security context needed to be updated.
Thanks Cloudshare!
