"Failed to start debugger" in VS Code when trying to debug test

Question

I'm trying to learn some Selenium and C# and I get the following error whenever I choose to debug a test:

[fail]: OmniSharp.Stdio.Host
        ************  Response (770.3988ms) ************ 
{
  "Request_seq": 35,
  "Command": "/v2/debugtest/getstartinfo",
  "Running": true,
  "Success": false,
  "Message": "\"System.InvalidOperationException: The debugger could not be started\\r\\n   at OmniSharp.DotNetTest.Services.DebugTestService.Handle(DebugTestGetStartInfoRequest request) in D:\\\\a\\\\1\\\\s\\\\src\\\\OmniSharp.DotNetTest\\\\Services\\\\DebugTestService.cs:line 42\\r\\n   at OmniSharp.Endpoint.EndpointHandler`2.<GetFirstNotEmptyResponseFromHandlers>d__19.MoveNext() in D:\\\\a\\\\1\\\\s\\\\src\\\\OmniSharp.Host\\\\Endpoint\\\\EndpointHandler.cs:line 198\\r\\n--- End of stack trace from previous location where exception was thrown ---\\r\\n   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()\\r\\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\\r\\n   at OmniSharp.Endpoint.EndpointHandler`2.<HandleRequestForLanguage>d__20.MoveNext() in D:\\\\a\\\\1\\\\s\\\\src\\\\OmniSharp.Host\\\\Endpoint\\\\EndpointHandler.cs:line 230\\r\\n--- End of stack trace from previous location where exception was thrown ---\\r\\n   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()\\r\\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\\r\\n   at OmniSharp.Endpoint.EndpointHandler`2.<Process>d__16.MoveNext() in D:\\\\a\\\\1\\\\s\\\\src\\\\OmniSharp.Host\\\\Endpoint\\\\EndpointHandler.cs:line 131\\r\\n--- End of stack trace from previous location where exception was thrown ---\\r\\n   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()\\r\\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\\r\\n   at OmniSharp.Stdio.Host.<HandleRequest>d__14.MoveNext() in D:\\\\a\\\\1\\\\s\\\\src\\\\OmniSharp.Stdio\\\\Host.cs:line 218\"",
  "Body": null,
  "Seq": 5990,
  "Type": "response"
}

I have absolutely no idea how to deal with that and will gratefully take any advice <3