Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 2348617 bytes) in /home/username/public_html/site1/wp-includes/plugin.php on line xyz
Fatal error: Out of memory (allocated 18612224 ) (tried to allocate 491520 bytes) in/home/username/public_html/site/wp-includes/canonical.php on line 257
Solution: Increase memory
Notes: Some plugins eat a lot of memory. Example WPML needs at least 64MB to run ok.