WP_MEMORY_LIMIT option allows you to specify the maximum amount of memory that can be consumed by PHP. This setting may be necessary in the event you receive a message such as “Allowed memory size of xxxxxx bytes exhausted”.
Increase the WP Memory Limit
In the root folder of your website, find the wp-config.php file and add the following line:
define( 'WP_MEMORY_LIMIT', '128M' );
NOTE: You must insert the line just BEFORE /* That's all, stop editing! Happy blogging. */ in the wp-config.php file.