If you had multiple clients talking to your app exactly at the same time, this is what could happen.

And as your app starts to handle more and more clients at the same time, the waiting time in a single request needs to be shorter and shorter to trigger the error.

### Fix Peewee with FastAPI

Now go back to the file `sql_app/database.py`, and uncomment the line:

```Python
db._state = PeeweeConnectionState()
```