Fatal Error!!!! [Plz Help]

I am getting that error on my site after activate that plugin

Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 18521993 bytes) in /home/content/54/11766754/html/ClassHomeCare/wp-content/plugins/w3-total-cache/lib/W3/ObjectCache.php on line 211

https://wordpress.org/plugins/w3-total-cache/