Resolving an error 503

If you see a 503 error message while WP Rocket is active, we recommend you check the following:

1

PHP memory: If you have deactivated the Preload option already, but the problem is still occurring, there could be a problem with your server resources. Follow this tutorial:
Increase PHP memory limit in WordPress

2

Database optimisation: Usually this problem appears when there are too many tables to be optimised which can prevent scripts to access it in order to execute their own tasks. If there is a large amount of items to be cleaned from your database (like thousands of revisions), we recommend to consult your hosting provider first. They should be able to give you precise advise about server possibilities.

3

Varnish: If your server uses Varnish cache, make sure to activate the Varnish Add-on in your WP Rocket settings.