MySQL failed connection attempts hitting max_connections

I run a couple of websites but I believe one of them is causing too many Connections Failed Attempts that causes max_connections variable to hit.

Currently, max_connections=2500 (already large) but total connections per hour due to failed attempts have become greater than 3000. How do I debug this? The httpd error log for the website does show a couple of PHP warnings/notices though. For example, using mysqli instead in the database config.

I don't think the failed connections are causing the max connections issue, but can you set log_warnings=2 and after a short time, view the error log to see if there is more information there? The error log would record something like "access denied for user 'user'@'host'..."

The command to set log_warnings=2 is:

set global log_warnings=2;

You can find the error log like this:

show global variables like 'log_error';

What version of mysql are you running?

Can you also show the output of:

show global variables like 'skip_name_resolve';

and:

show global status like 'max_used_connections';

StackExchange Database Administrators Q#139305, answer score: 2