Hi ,

Is the issue only with your login or is it happenning with everyone ?

Have you tried on any other browser ?

Mostly its a cache issue , try clearing the browser cache and see if it works.

If you are restarting . make sure to clear the cache before restarting the server . 

Possible issue could be because of truncation of cache from db or server , did you truncated any of the cache table?

We had similar issue, got solved when we deleted the marker file and restarted the server.

Do not just truncate , ask for exact steps to delete cache from pega and follow the instruction

Faced same problem, and restarted server after clearing the browser cache, as suggested in the discussion above, and also the rule cache.

Thanks to all it is working now.