Hello everyone, 

I’ve encountered some problems with player matching when running my experiment both locally and on Heroku.
In my experiment, participants are supposed to be grouped into 6-person groups, and they are re-matched with different people in each round. The experiment runs smoothly when I set num_demo_participants=4 and PLAYERS_PER_GROUP=4, and the players are matched successfully. However, when I set the group size to 6 or larger, the experiment fails to run consistently. It occasionally works, but the behavior is quite random and unstable. 

Steps I've Taken:
1.    Database Switch: Initially, I thought the issue was related to db.sqlite3, so I switched both my local and Heroku databases to PostgreSQL. After the switch, the experiment worked the first time I ran ‘otree devserver’, but then it started failing again during subsequent runs.
2.    oTree Version Downgrade: I also tried downgrading my oTree version from 5.10.4 to 5.8, but the experiment remains inconsistent. Sometimes it works, but most of the time it doesn't.

The problem seems intermittent, and I am unsure whether it's related to the database migration, the version of oTree, or something else in my setup.
If anyone has encountered similar issues or has suggestions, I would greatly appreciate any advice.

Best wishes