when you change the system password of the user under which the TC services run, you have to set it in the service logon properties too.
the FSC Service need to run with a user account, it cannot run as 'Local System'
What means: I changed system password?
You mean, you changed the password from the user which is running the FSC service.
You need to change the 'Logon information' of the FSC service and update the password