Pages doesn’t load when cache hasn’t been generated

Just migrated the site to a new server, everything’s working alright, all plugins are up to date.

The error is as following:

Basically, when caching is on and if the page hasn’t been previously generated on cache I get a blank page, no errors.

If I’m not logged in to the WP Dashboard, every new page I visit for the first time throws me a HTTP ERROR 500. Once reloading the newly visited page and once cache has generated, it shows all content correctly.

If I’m logged in to the WP Dashboard, I’m not able to load any public pages, they all come blank, no errors. Dashboard is not affected.

Thanks for your help!