Same issue here:
Fatal error: Cannot redeclare wp_cache_add() (previously declared in /var/www/vhosts/domain.com/httpdocs/wp-includes/cache.php:30) in /var/www/vhosts/domain.com/httpdocs/wp-content/plugins/memcached/object-cache.php on line 19
Please, HELP ))
This has been answered here https://ww.wp.xz.cn/support/topic/cannot-redeclare-wp_cache_add-2/
copy the file to wp-content instead of activating it in the backend.
Hello,
probably you should make the “copy the file to wp-content instead of activating it in the backend.” message more attractive (of red color, bold, etc…) I`ve just posted a one-star review… Going to delete it…
Update: Copying object-cache.php /wp-content
Running WP 5.7.2 on PHP 7.4
Perhaps this plugin doesn’t handle a non-standard CONTENT path?
Fatal error: Cannot redeclare wp_cache_add() (previously declared in xxx/docs/cms/wp-content/object-cache.php:19) in xxx/docs/cms/wp-content/plugins/memcached/object-cache.php on line 19
