A few days ago, I did a web server migration, moving my sites that I manage from Apache to Nginx.
When a Prestashop store was moved, I was surprised to discover that all the pages viewed (home, articles, management console, etc.) were all white (but without any error code visible to the user).
While digging through the web server logs, I realized that a Symfony module was trying to access files that existed, but were not valid for it (because the web server had changed).
To resolve the issue, you need to manually clear the Prestashop cache
To delete the cache, you need to delete the PRESTASHOPPATH/var/cache folder
This is sort of the root folder of the store, and it varies depending on your installation.
Once done, the store should function normally again.
All that remains is to regenerate the cache by going to Advanced Settings > Performance > Clear Cache (the blue button at the top right of the window).
