Workload Automation DE 12.0
Desktop Client on Windows 7
We could see that the Workload Automation service was not running on the WA server.
In the errors.txt we could see the following error
20180510 22:52:54.148 [relationaldatabase] [ERROR] DM.Appl.NTSCHED.88: [2018-05-10_22:52:54.101] SQLCode: 0 SQLState: null Message: The connection is closed
The problem happened because the connection was closed from the database end.
It could have been due a network error
Restarted the the Workload Automation DE service and it came up fine