To address memory limit issues, there are two paths:

• Adjust it yourself
• Contact your hosting company

1. Edit your wp-config.php file and enter something like:

define('WP_MEMORY_LIMIT', '512M');

WordPress memory can be different to the server – you need to set this regardless of server memory settings

https://codex.wordpress.org/Editing_wp-config.php#Increasing_memory_allocated_to_PHP

2. If you have access to your PHP.ini file, change the line in PHP.ini
If your line shows 256M, try 512M.

memory_limit = 512M ; Maximum amount of memory a script may consume (512MB)

3. If you don’t have access to PHP.ini try adding this to an .htaccess file:

php_value memory_limit 512M

4. If none of the above works, then talk to your host.