ERR_NGROK_SHIP_CHECK_PATH_ILLEGAL_CHARACTER: Health check NAME path PATH must not contain '?' or '#' - ngrok documentation

What does ERR_NGROK_SHIP_CHECK_PATH_ILLEGAL_CHARACTER mean?

ngrok returns ERR_NGROK_SHIP_CHECK_PATH_ILLEGAL_CHARACTER with this message:

Health check <NAME> path <PATH> must not contain '?' or '#'.

Where can I get more help with ERR_NGROK_SHIP_CHECK_PATH_ILLEGAL_CHARACTER?

Email support@ngrok.com and include the error code.