What was going on
Adding a new Presto data source with an empty password is impossible: the form shows "Please fill out this field" and there is no way to complete the add-data-source flow. The reporter wants basic auth with an empty password.

What fixed it
This was a GrowthBook form-validation bug, fixed by the maintainer the same day it was reported. Pull the latest Docker image (post-fix build) and restart the container; data sources with empty passwords can then be saved.