How to increase the 'WP_MEMORY_LIMIT'?
Having enough (working) memory is important for your WordPress website. When there is too little memory available the website can react slowly and for example importing products can take much longer than normal. There is an error message that's related to this: " Fatal error WP memory limit exhausted" if you see this error message you need to increase this also.
To increase the memory of your WordPress website you need to log in to your FTP server. Then you can open the file wp-config.php in the root directory of your server. Here you can then add the code below.
// set WordPress memory define('WP_MEMORY_LIMIT', '512M');