MySQL 1182: Connection was closed.

What is MySQL 1182: Connection was closed.

Check the MySQL server logs. Run `tail -n 100 /var/log/mysql/error.log` to see recent error messages that might indicate why the connection was closed.

Verify MySQL server is running: `sudo systemctl status mysql` or `mysqladmin -u root -p status` to ensure the MySQL service is active.

Check for network issues: Use `ping` or `traceroute` to ensure there's network connectivity between your application server and the MySQL server.

Examine the `maxconnections` setting: Run `SHOW VARIABLES LIKE "maxconnections";` to see if you're hitting the maximum number of connections allowed.

Inspect open connections: Execute `SHOW STATUS LIKE "Threadsconnected";` to see how many connections are currently open and compare it with the `maxconnections` value.

Review your application code or configuration to ensure it's correctly managing database connections, such as properly closing them when done.

If using a pool of connections, check its configuration to ensure it matches the capabilities of your MySQL server, specifically the `max_connections` setting.

Investigate for any ongoing large queries that may be causing timeouts or locking issues: `SHOW FULL PROCESSLIST;` to see current executing queries.

Increase the connection timeout settings if necessary, by adjusting `waittimeout` and `interactivetimeout`: `SET GLOBAL waittimeout = 28800;` and `SET GLOBAL interactivetimeout = 28800;` for a start, adjusting values based on your needs.

If possible, temporarily increase `maxconnections` to see if the problem persists: `SET GLOBAL maxconnections = 1000;` (adjust the number based on your server's capability and needs).

Remember to revert any temporary changes that are not suitable for your production environment after testing.