TabPy uses Tornado 5.1.1. To it to your Python environment run
pip install tornado==5.1.1
and then try to start TabPy again.
Check your Python version (python -V
command) - TabPy doesn't work with
Python 3.8. It is recommended to use Python 3.6 or 3.7 for now.
The root cause for the failure - Tornado issue.