Where are the PHP error messages (error_log) stored?

If enab­led, Apa­che stores all PHP error mes­sa­ges of your web­site in a sepa­ra­te log file. This includes war­nings, hints and also errors, depen­ding on which log level you have defi­ned befo­re. Bes­i­de the stan­dard loca­ti­ons for the error.log you can also defi­ne an indi­vi­du­al loca­ti­on, for exam­p­le with PHP, you can find more about that here.

On Linux, Apa­che places the error.log file here:

/var/log/apache2/error.log

Alter­na­tively you can find the error mes­sa­ges here:

/var/www/vhosts/system/{domain}/logs/error_log