500 Error when getting tasks

Workspace 77388 here and we've got a C# utility that's been working for quite some time now. Recently, within the last few weeks, the response from the following request is throwing back a 500 error (internal server error).

https://app.liquidplanner.com/api/workspaces/77388/tasks/?filter[]=reference contains TFS&filter[]=name contains TFS&include=dependencies,tags

I've tried the same "tasks" get request at the LiquidPlanner Classic API web interface and the "Try It!" button just spins...

https://developer.liquidplanner.com/reference/get_workspaces-workspace-id-tasks

Can someone help diagnose this?