Issue Summary
Opening the Workload report for Jira Service Management project will fail with an HTTP 500 error and a "null" response received in case any of the project's agent accounts is deactivated.
Steps to Reproduce
- Create a new Jira Service Management project and assign issues to some agent accounts. Check the "Workload" report — it can be loaded successfully.
- Disable the agent account that still has any issues assigned. Loading of the "Workload" report will fail with an HTTP 500 error.
Expected Results
Prior to the changes introduced at JSDSERVER-6047 disabling agent accounts that had issues assigned didn't trigger an error ("Workload" report simply didn't have any issues listed for such accounts)
Actual Results
The "Workload" report fails to load. However, it is still possible to show information for all agents (with the "All agents" option from the drop-down list).
The error doesn't manifest in application logs (no error/exception reported) and could be observed only in access logs (as requests with HTTP 500 error codes)
Workaround
As a potential workaround, you could re-enable disabled agents' accounts or re-assign their issues to active accounts. Further workarounds will be added here when available (if any)
High 
