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 the wp-config.php file just before the line that says ‘That’s all, stop editing! Happy blogging.’
define( ‘WP_MEMORY_LIMIT’, ‘256M’ );
This code tells WordPress to increase the PHP memory limit to 256MB.
Once you are done, you need to save your changes and upload your wp-config.php file back to your server.
You can now visit your WordPress site and the memory exhausted error should disappear now.