My Replit app (not deployed in public yet) keeps crashing

Question

I am building an app on Replit and it says "Your app crashed" - I am a completely non-technical person, so I don't know how to fix it.

I asked Replit Assistant and it seems to have identified the reason and is doing something to fix. But the "Run shell command" seems to take forever.

I don't know if it has to do with the fact that I've exhausted by free 'checkpoints' and need to upgrade.