Issue with TestProject Task in Release Pipeline

I have a “Release” Pipeline that contains the “TestProject” Task. I have verified that the correct “Project ID”, “Job ID”, and “API Key” are being used.

When run, I get the following error: System.Management.Automation.RuntimeException: Start TestProject Test Run failed, received HTTP 404 but expected HTTP 200. Error: .StatusDescription —> System.Management.Automation.RuntimeException: Start TestProject Test Run failed, received HTTP 404 but expected HTTP 200. Error: .StatusDescription

The full log:

2022-05-17T18:56:07.8202267Z ##[section]Starting: TestProject Run Job
2022-05-17T18:56:07.9124904Z ==============================================================================
2022-05-17T18:56:07.9125510Z Task : TestProject Start Job
2022-05-17T18:56:07.9125942Z Description : Task for performing a Call to start a TestProject Job.
2022-05-17T18:56:07.9126176Z Version : 1.0.0
2022-05-17T18:56:07.9126492Z Author : Dieter Dornmayr
2022-05-17T18:56:07.9126900Z Help :
2022-05-17T18:56:07.9127135Z ==============================================================================
2022-05-17T18:56:07.9491836Z ##[warning]Task ‘testproject-run’ (1.0.0) is using deprecated task execution handler. The task should use the supported task-lib: azure-pipelines-task-lib/README.md at master · microsoft/azure-pipelines-task-lib · GitHub
2022-05-17T18:56:07.9505545Z Preparing task execution handler.
2022-05-17T18:56:08.6360848Z Executing the powershell script: C:\azureAgent_work_tasks\testproject-run_0ac7e960-2688-4cb8-a4d1-3e6708af0b9a\1.0.0\task.ps1
2022-05-17T18:56:08.9172455Z Executing TestProject Test Run with https://api.testproject.io/v2/projects/
2022-05-17T18:56:08.9173885Z
2022-05-17T18:56:08.9174287Z
2022-05-17T18:56:11.6835720Z ##[error]System.Management.Automation.RuntimeException: Start TestProject Test Run failed, received HTTP 404 but expected HTTP 200. Error: .StatusDescription —> System.Management.Automation.RuntimeException: Start TestProject Test Run failed, received HTTP 404 but expected HTTP 200. Error: .StatusDescription
2022-05-17T18:56:11.6840623Z — End of inner exception stack trace —
2022-05-17T18:56:11.6841270Z at System.Management.Automation.Runspaces.PipelineBase.Invoke(IEnumerable input)
2022-05-17T18:56:11.6841746Z at System.Management.Automation.PowerShell.Worker.ConstructPipelineAndDoWork(Runspace rs, Boolean performSyncInvoke)
2022-05-17T18:56:11.6842270Z at System.Management.Automation.PowerShell.Worker.CreateRunspaceIfNeededAndDoWork(Runspace rsToUse, Boolean isSync)
2022-05-17T18:56:11.6842850Z at System.Management.Automation.PowerShell.CoreInvokeHelper[TInput,TOutput](PSDataCollection1 input, PSDataCollection1 output, PSInvocationSettings settings)
2022-05-17T18:56:11.6844093Z at System.Management.Automation.PowerShell.CoreInvoke[TInput,TOutput](PSDataCollection1 input, PSDataCollection1 output, PSInvocationSettings settings)
2022-05-17T18:56:11.6844669Z at Microsoft.TeamFoundation.DistributedTask.Handlers.LegacyVSTSPowerShellHost.VSTSPowerShellHost.Main(String args)
2022-05-17T18:56:11.6996048Z ##[error]LegacyVSTSPowerShellHost.exe completed with return code: -1.