There has been a critical error on this website.

Hello everyone,

I all of a sudden have this error that prevents my site from loading:

There has been a critical error on this website.
Learn more about debugging in WordPress.

Note: I don’t know when this started I just noticed it last night.

After some reading and following some troubleshooting tips I came to the following:

If I deactivate a plugin “W3 Total Cache” that above error message disappears but I still get a blank white page.
I checked my email and found that the plug was updated Dec 16 so I rolled it back to a previous version and activated it but that did not help.
I rolled it back even further and further and that did not help either. I then updated it to current version and still no progress. Same result, if I activate it I get the error message, deactivate it and get a blank page.

Am I on the right track or wasting my time?
If I’m on the right track, what else should I do?
If on the wrong track, what other troubleshooting tips do you have for me?

Thanks

Edit:

I went back and tried to edit my contact page using Elementor (went to admin, pages and clicked on Edit using Elementor) and got the following error (which I get when trying to edit any page):

There has been a critical error on this website.

Learn more about debugging in WordPress.

Uncaught Error: Call to undefined function ctype_xdigit() in /hermes/walnacweb04/walnacweb04ac/b2714/moo.totalfactoryautomati/wp_site_1600286052/wp-content/themes/astra/inc/core/common-functions.php:50
Stack trace:
#0 /hermes/walnacweb04/walnacweb04ac/b2714/moo.totalfactoryautomati/wp_site_1600286052/wp-content/themes/astra/inc/class-astra-dynamic-css.php(172): astra_get_foreground_color(‘d94948’)
#1 /hermes/walnacweb04/walnacweb04ac/b2714/moo.totalfactoryautomati/wp_site_1600286052/wp-includes/class-wp-hook.php(287): Astra_Dynamic_CSS::return_output(‘#masthead .ast-…’)
#2 /hermes/walnacweb04/walnacweb04ac/b2714/moo.totalfactoryautomati/wp_site_1600286052/wp-includes/plugin.php(212): WP_Hook->apply_filters(‘#masthead .ast-…’, Array)
#3 /hermes/walnacweb04/walnacweb04ac/b2714/moo.totalfactoryautomati/wp_site_1600286052/wp-content/themes/astra/inc/core/class-astra-enqueue-scripts.php(250): apply_filters(‘astra_dynamic_t…’, ”)
#4 /hermes/walnacweb04/walnacweb04ac/b2714/moo.totalfactoryautomati/wp_site_160

The page I need help with: [log in to see the link]