After upgrading php to 7.4, my website went blank with w3 total cache.

Hello,

Thank you for reaching out and I am sorry about the issue you are experiencing.
W3 Total Cache is compatible with the latest PHP 8 and this means that it’s also compatible with any previous versions.
I can see that you are using some other caching solution.
I would recommend completely removing and re-install W3 Total Cache. Make sure that the other caching plugin is completely removed as well.
1. Check .htaccess File (make a backup)
W3TC will create many directives in the .htaccess file to control the caching behavior. Each section will start and end with comments like “#BEGIN W3TC Page Cache core” and “#END W3TC Page Cache core”.
Ensure that no residual entries are leftover in your .htaccess file after deleting the plugin.
2. Delete wp-content files and folders
– cache folder
– w3tc-config folder
– object-cache.php (if exists)
– advanced-cache.php (if exists)
– db.php (if exists)
– upgrade folder
– delete w3-total-cache folder in wp-content/plugins/ (if exists)
3. Delete Cached Files from CDN (if using CDN)
Besides deleting all the relevant files, if you use CDN then ensure to purge the cached content from your CDN. This is necessary when you enabled minify option in W3TC settings. You should delete the minified and combined scripts and CSS files from your CDN server to avoid the site breaking on the browser.
4. Go to your wp dashboard and re-install W3 Total Cache
I hope this helps!

Hello,
Thank you for your feedback.
I’ve checked your website and I am seeing it loading just fine.
After inspecting the website I can see that the following options are enabled:

<!--
Performance optimized by W3 Total Cache. Learn more: https://www.boldgrid.com/w3-total-cache/

Object Caching 0/306 objects using disk
Page Caching using disk: enhanced 
Lazy Loading
Minified using disk

Served from: www.atomythedream.com @ 2021-08-09 10:28:35 by W3 Total Cache
-->

Thanks!