Hi @acecauis,
The Custom database connection gives the responsibility for managing users to Auth0. That is the central point for any user manipulation. Users need to be both added and deleted from it. Your Auth0 applications will try to access the users saved in the Auth0 User Store so when you’re about to make any change to the database, make it through the Management API.
For your tests use the Management API to delete users instead of deleting them directly from the database
If you have any other question feel free to reach out.
Have a good one,
Vlad