NM. It was an issue with all custom test cases. Should be good now.

I have test cases in my current Kata and I get the error 'Test didn't pass: Unknown error'

Do you have any test cases? We need to clean up the error messaging caused by some recent changes, but it looks like people are getting that error because they are submitting code that doesn't have any test cases, which is why it was working when you submitted (because you were using the kata author's test cases instead).