I am using WP-Super Cache for caching which worked fine until yesterday. This is how the problem started.
1. I deactivated all plugins to troubleshoot a different issue.
2. WP-Super Cache generated 3 error messages upon deactivation as I deactivated it without switching off the cache first.
Error message 1: Warning: implode() [function implode]:Invalid arguments passed in /home/virtudwt/public_html/wp-content/plugins/wp-super-cache/wp-cache.php on line 2498
Error message 2: Warning: implode() [function implode]:Invalid arguments passed in /home/virtudwt/public_html/wp-content/plugins/wp-super-cache/wp-cache.php on line 2499
Error message 3: Warning: Cannot modify header information - headers are already sent by (output started at /home/virtudwt/public_html/wp-content/plugins/wp-super-cache/wp-cache.php on line 2498) in /home/virtudwt/public_html/wp-content/plgins/ylsy_permalink_redirect.php on line 423
I ignored these messages and reactivated WP-Super Cache later. Now the plugin isn't caching anything at all. Testing the cache throws the following error.
Fetching http://www.virtualpreacher.org/ to prime cache: OK
Fetching first copy of http://www.virtualpreacher.org/: OK (1.html)
Fetching second copy of http://www.virtualpreacher.org/: OK (2.html)
The pages do not match! Timestamps differ or were not found!
I quickly concluded this is something specific to WP-Super Cache and tried Green Cache, Hyper Cache, Quick Cache and W3 Total Cache. None of them works.