I think that are a not enough information, but the first two things that come to my mind as you haven't given the information:

• Download the extension Python and Python Debugger
• Run the script without debugging instead of with debugging

Or maybe this helps: Issue not connecting to target at localhost: 9222 Could not connect to debug target at http://localhost: 9222 Could not find any debuggable target

For further help there would be more information needed (code snippet, what is working and what not)