If your application can't reach the MySQL/MariaDB server, work through the most common causes below.
1. Use 127.0.0.1, not localhost
In your application's configuration (for example Laravel's .env), set the database host to 127.0.0.1 instead of localhost. On Linux, localhost makes MySQL connect over a Unix socket, while 127.0.0.1 forces a normal TCP connection on port 3306, which is usually what you want.
2. Check your credentials
Confirm the database name, username and password match what you created in Ploi (Server > Databases). A mismatch is the most common cause of "access denied" errors.
3. Confirm the user may connect
Ploi-created users may connect from the server itself. If you connect from another server, you must also allow remote access — see How do I allow remote access to MySQL or MariaDB.
4. Make sure the database server is running
SSH into your server and check the service:
systemctl status mysql
If it isn't running, start it with systemctl start mysql and check the logs for why it stopped.
