Scenario: Some of the users are having issues logging it to the systems (users are hanging, the system keeps crashing) is is only affect some but not all users
Possible Resolution:
Check with the company concerned if they have installed any updates to their PC/Laptops (Windows Based).
We have found this update is affecting Filemaker
https://support.microsoft.com/en-gb/help/4512192/august-20-2019-kb4512192-cu-for-net-framework