An error 500 means there has been an 'internal server error'. In most circumstances, this is as a result of Pyrusium not establishing connection to the main GP clinical system.
1) Close Pyrusium
2) Close your clinical system and ensure there are no other instances of the system running (to do this, go into task manager and check the processes)
3) Re-open the clinical system
4) Re-open Pyrusium
This should fix the issue. If it does not, we recommend restarting the workstation and then trying from step 3.