As we described in previous blog, occasionally a user will get “Sorry, something went wrong. An unexpected error has occurred.” error when accesses a site on SharePoint 2013.
Even you clear browser cache and open new browser and try again, you might still have the same issue. This seems to happen in SharePoint 2013 farm with multiple web applications using the mixed authentications. Beside the server configuration workarounds I have provided in previous blog, I’ve found another quick and easy workaround for end users.
The workaround is very simple - sign in as different user using the following URL.
You could enter the same user ID and password to login again. The reason you are not able to login might be related the distributed cache issue. The cached user authentication is corrupted and cannot authenticate the current user that has been cache form client cookie.
You might also try to run browser “Run as different user” option. Just right-click the IE icon while holding the shift key down and click on “Run as different user.” Once logged in, just navigate to the SharePoint site.
Sign in as different user will create a new session and will not use the cache. As a result, you should be able to login after several tries.