Failure to complete

I did the auto upgrade to 2.8. My dashboard tells me I am now using the latest version 2.8 and everything works fine. However, it also tells me that the auto upgrade did not complete and to attempt the install again. When I do I get a server error every time. Plugin auto upgrades give me the same server error. As part of the auto upgrade to 2.8 the database upgrade page appeared to complete successfully, so I don’t think that is the problem. There is nothing telling me what part of the upgrade failed to complete. Any suggestions?