Hostinger MySQL–PHP Connection Setup

I have a single MySQL database sitting on my Hostinger account and three separate custom-built PHP sites that need to talk to it. At the moment the connection fails whenever the login page tries to authenticate a user, so I suspect the issue is buried somewhere in the backend configuration—possibly wrong credentials, hostnames, or overlooked privileges inside phpMyAdmin.

Here’s what I need from you:

• Inspect the current hPanel and phpMyAdmin settings, make sure the database user has the right privileges, and confirm the host names for all three sites.
• Review each site’s PHP connection file, tidy up the mysqli / PDO code as required, and verify that user-authentication queries run without errors.
• Test end-to-end on all three domains so logging in, registering, and basic data retrieval work cleanly. If you spot best-practice gaps (prepared statements, password hashing, etc.), patch them on the spot.

Once everything is humming, just hand over the updated connection scripts and a brief note of what was fixed so I can keep it documented.