Troubleshooting

Symptom	Cause and fix
Exit code 2	`SNACK_AND_LIFT_EMAIL` or `SNACK_AND_LIFT_PASSWORD` is not set.
Login fails 7 times, then exit 1	Wrong e-mail or password, or the account is not in this `chrome_profile` (the site keeps accounts in the browser). Register again with `--keep-open`.
Exit code 3 and MISMATCH	The My Bookings page does not list what the bot booked. Run again; check whether a class was full.
Warnings "attempt 2 of 7"	The site's failure rate is on; this is the retry at work (step 9).
Chrome warns about the password	Chrome flags weak passwords such as `12346`; choose another.
No window in Docker	The container is headless by design; use `--screenshot-dir`.