So I am still having this problem. 
I even created a new virtual environment and reinstalled rasa, copied my files including the domain file, and retried rasa train and still I get this glorious error :
YamlValidationException: Failed to validate ‘C:\xxxx\bots\xxxx\domain.yml’. Please make sure the file is correct and all mandatory parameters are specified. Here are the errors found during validation
And no list of errors ever follows. I have checked the file in both yamillit and yaml checker and they both say it’s valid. What gives? What am I missing?
Any help or suggestions would be greatly appreciated. 