This issue primarily affects those on Sitecore 9, but it's useful to understand what's happening regardless.
One such symptom of this issue and how it can be resolved is when you are trying to login to your Content Management (CM) environment but after entering in the credentials, clicking Log in it just spins and eventually gives you an Error 503 connection timed out exception. You may even be able to browse the site normally (on the web database) through normal mode while on the CM environment, but logging in never works. With that scenario it can be confusing as to what is happening and therefore the following solution may apply.
Possible Solution
Let's face it there could be a multitude of issues going wrong, but I've found this solution to help in this scenario. One thing to check how many (if any) SC_TICKET records exist within the Properties table of the Core database.
Let's do that by first logging in to your Core db and opening up a query editor. Once there enter the following command and execute it.
SELECT FROM [Properties] WHERE [Key] LIKE '%SC_TICKET_%'If your Properties table has a LOT of SC_TICKET entries this can really put a drag on performance of the backend authoring. Especially when it comes to logging in.
If this value is in the 10's or 100's of thousands I would highly recommend clearing it. Now, keep in mind, this will log out anyone currently logged into the system so best to let folks know or perform it after hours.
DELETE FROM [Properties] WHERE [Key] LIKE '%SC_TICKET%'If you want, you can be more selective by clearing say just the admin users.
DELETE FROM [Properties] WHERE [Key] LIKE '%SC_TICKET%' AND [Value] LIKE '%admin%'Once you have performed this, I recommend restarting your Sitecodre CM instance.
