Hello,
I am still rather inexperienced. After deactivating ACF Pro, my website is down and I can’t access wp-admin. How can I activate it again or solve the problem?
Thanks in advance.
You can’t.
You will need to enable debugging https://developer.wordpress.org/advanced-administration/debug/debug-wordpress/
Find the code that is causing the fatal error, likely in the theme’s functions.php file and comment it out to get wp-admin to run so you can activate the plugin.