I'm sure you've checked for this already but if you didn't check the basics first.
1. Check to ensure that licensing capabilities for UPC have been enabled for the user.
2. Check the UPC configuration for the user.
3. Check the Presence server make sure that the Application Profile Configuration is correct.
4. Is the user account listed in CUCM? If not, synchronize CUCM with AD.
5. Delete the UPC account for the user and create a new UPC account.
6. There is the latest version of CUPC its 8.5.6 it works with your version of presence 8.5.3 server.
I hope this helps.