Most of the time we have face the WordPressWordPress WordPress (WordPress.org) is a content management system (CMS) based on PHP and MySQL that is usually used with the MySQL or MariaDB database servers but can also use the SQLite database engine. memory limit issue. There was lot of reasons behind this issue. This may happen with shared hosting.
some plugins are not able to perform their operations from the available memory.
To fix the issue just copy and paste below code into your
wp-config.php file located in the root directory of your WordPress setup.
define( 'WP_MAX_MEMORY_LIMIT', '256M' );