I disabled w3tc and website was fine for a week. One of the websites hosted on the server made the server unresponsive ( critically low on RAM). It could be the website I am working on.
I enabled the cache plugin, cleared the cache and disabled the plugin again. Then this error started to show:
Label 'http' already defined in
/var/www/vhosts/website/httpdocs/wordpress/wp-content/plugins/w3-total-cache/lib/W3/PgCache.php(1356) : eval()'d code on line 2
I 'fixed' the blank page and error by renaming the plugin folder name from 'w3-total-cache' to 'w3-total-cache-disabled'.
This however broke the image upload, additionally the images already uploaded were not visible in Add Media screen. So no images could have been added po posts.
I enabled the w3tc plugin again and disabled the page cache, leaving the Database cache and Object cache enabled.
How can I fix that error that shows up when I enable Page cache?