BayesianParameterSampling parameter space error

I've posted an issue on the MS forum, and will link it here for easier reference: https://docs.microsoft.com/en-us/answers/questions/760594/error-the-provided-hyperparameter-space-cannot-be.html

The same error occurs with any type of parameter sampling. I've followed multiple examples that follow this pattern so I'm not sure what the problem here could be.