Thank you for following this up with us.
We have shut down the instance as it didn't make sense to keep it running.
Please find the logs in the [9977-workbench-error.txt]attachment which we recorded earlier. Please check if it may be of any help.
And yes, we tried restarting the app-service [both Workbench Ui and swagger API service]. It didn't fix the problem for us. : /answers/storage/temp/9977-workbench-error.txt