Hey There,
By default, WordPress will attempt to increase memory allocated to PHP to 40MB (code is at the beginning of /wp-includes/default-constants.php) for single site and 64MB for multisite, so the setting in wp-config.php should reflect something higher than 40MB or 64MB depending on your setup. So even if you PHP memory in the server is 1GB, WordPress will only set to 40MB. We recommend that you increase your WordPress memory allocated to PHP. To increase it, please edit your wp-config.php file and insert these lines:
define( 'WP_MEMORY_LIMIT', '256M' );
define( 'WP_MAX_MEMORY_LIMIT', '512M' );
You can add it before the line
/*That's all, stop editing! Happy Blogging. */
And also make sure that you are using the correct PHP version. WordPress 4.7 requires at least 7.0 (https://wordpress.org/about/requirements/). This could possibly be the cause of the issue. In most cases you cannot update your PHP version yourself and need to contact your host about this. The upgrade process is an easy process and should be something your host can do for you without affecting your website or charging you for it. Here’s a letter you can send to your hosting company:
Dear host,
I'm interested in running the open-source WordPress <https://wordpress.org/> web software and
I was wondering if my account supported the following:
- PHP 7 or greater
- MySQL 5.6 or greater
- The mod_rewrite Apache module
- HTTPS support
Looking forward to your reply.
Hope this helps. Kindly let us know.