Debug Tests Fails with "Multiple scenarios are not supported"

When attempting to execute a Debug Test, you may be met with this pop-up error message:

A 'Debug Test' only supports running with one engine.  When executing a test, each scenario defined requires its own dedicated engine, which means that a 'Debug Test' likewise only supports running with one scenario.

There are two ways in which your test may try to run more than one scenario:

• If executing your test via a Taurus YAML configuration file, you may have defined more than one scenario under the execution: section. You will need to remove additional scenarios so that the YAML only executes one scenario. 
  
  
• You may have enabled End User Experience Monitoring.  If so, this feature requires an additional engine, as the End User Experience (EUX) test is considered its own scenario apart from your main test scenario.  This feature is not supported for Debug Tests, so make sure to disable it before running it in debug mode.