This article for increase memory limit in WordPress. Below are some ways to increase memory limit.
Edit wp-config.php file
First you need to edit the wp-config.php file on your WordPress site. It is located in your WordPress site’s root folder, and you will need to use an FTP client or file manager in your web hosting control panel.
Next, you need to paste this code in wp-config.php file just before the line that says ‘That’s all, stop editing! Happy blogging.’
<?php
define( 'WP_MEMORY_LIMIT', '256M' );
?>
Edit php.ini file
If you have access to your php.ini file, change the line in php.ini. If your line shows 64M try 256M
memory_limit = 256M ; Maximum amount of memory a script may consume (64MB)
Edit .htaccess file
Add this following line to an .htaccess file
php_value memory_limit 256M