Error running tests (.net core)

[reflash]

Hey,
I've tried to run tests via Neptune, but it fails with the following

To run tests we use dotnet test with XUnit framework.

It seems that happens only when I try "Run All" tests, it works if I click individual tests to run in editor.
Trying to run individual tests in Test Explorer fails with:

Error running command neptune.runTest: Request failed with status code 500. This is likely caused by the extension that contributes neptune.runTest.
Running test failed - {stack: Error: Request failed with status code 500
at createError (c:\Users\reflash.vscode\extensions\lambdafactory.neptune-1.3.6\neptune.js:9959:15)
at settle (c:\Users\reflash.vscode\extensions\lambdafactory.neptune-1.3.6\neptune.js:12215:12)
at IncomingMessage.handleStreamEnd (c:\Users\reflash.vscode\extensions\lambdafactory.neptune-1.3.6\neptune.js:24755:11)
at IncomingMessage.emit (events.js:187:15)
at endReadableNT (_stream_readable.js:1092:12)
at process._tickCallback (internal/process/next_tick.js:63:19), message: Request failed with status code 500, config: [object Object], request: [object Object], response: [object Object]}