Proxy errors on MSUnitTests, 3.1

   [TestMethod]
    public void TestUserInheritance()
    {
        var _c = new Controller();

        _c.AddEmployee("Dirk");
        _c.AddUser("Wilma");
        _c.AddProjectmanager("Jens");

        Assert.AreEqual(_c.GetUsers().Count, 3);
    }

The project builds perfect and I'm on .net core 3.1 When I run the tests it just does nothing and throws stuff in the Test Output

     Test data store opened in 0.096 sec.
        [2/29/2020 9:18:48.542 PM] ---------- Discovery started ----------
        Microsoft.VisualStudio.TestPlatform.ObjectModel.TestPlatformException: Testhost process exited with             
        error: Failed to create CoreCLR, HRESULT: 0x80070057
        . Please check the diagnostic logs for more information.
          at 
    Microsoft.VisualStudio.TestPlatform.CrossPlatEngine.Client.ProxyOperationManager.ThrowExceptionOnConnectionFailure(Int32 connTimeout)
       at Microsoft.VisualStudio.TestPlatform.CrossPlatEngine.Client.ProxyOperationManager.SetupChannel(IEnumerable`1 sources, String runSettings)

   at Microsoft.VisualStudio.TestPlatform.CrossPlatEngine.Client.ProxyDiscoveryManager.DiscoverTests(DiscoveryCriteria discoveryCriteria, ITestDiscoveryEventsHandler2 eventHandler)
[2/29/2020 9:18:49.386 PM] ========== Discovery aborted: 0 tests found (0:00:00.8389177) ==========

and it also throws this huge error.

[2/29/2020 9:40:40.785 PM] ========== Run aborted: 0 tests run (0:00:00.282598) ==========
StreamJsonRpc.RemoteInvocationException: The following TestContainer was not found 'C:\Users\Refactor\Documents\GIP\Taken\Software\Taak09-19;11;2019\UnitTests\bin\Debug\netcoreapp2.0\UnitTests.dll'
   at StreamJsonRpc.JsonRpc.<InvokeCoreAsync>d__96`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.TestWindow.Host.TestStoreHandler.<AddSourceBasedTestsAsync>d__23.MoveNext()

I've tried doing a clean->build, restarting vs2019, updating resharper, ... I've also tried updating the needed nuget packages but that didn't have an effect either