“Test Connection” fails. What do I check?

1. IP address — from another machine, 127.0.0.1 won’t work; use the server’s LAN IP.
2. Firewall — is the inbound rule for port 3306 active on the server?
3. Login/password — a typo when creating the account?
4. MySQL 8+ authentication — see Section 5; use mysql_native_password.

Applicable to Project Manager running on a shared MySQL/MariaDB database (multi-user/team setup)