You are using an old oTree version Your otree package is out-of-date (version 2.1.35; latest is 3.3.6). You should upgrade with: "pip3 install --U otree" and update your requirements_base.txt.
You are using a proper database (Postgres, MySQL, etc).
DEBUG mode is off
You are using a server other than runserver.
Sentry is configured.
No password protection To prevent unauthorized server access, you should set the environment variable OTREE_AUTH_LEVEL.
Your database appears to be synced.
No worker process found

The worker process enables the following functionality:

  • Browser bots
  • If your study has timeouts on pages (with timeout_seconds), then the timeoutworker will automatically advance a user when they exceed the timeout, even if they close their browser.

In your app dashboard, make sure the second dyno is turned on.