When wanting to enter the Admin of my Wordpress, I enter the keys and it is impossible to access the admin panel. And I get this message:
Fatal error: Call to undefined function wp_raise_memory_limit () in /home/u876614381/public_html/wp-admin/admin.php on line 141
Apparently this problem occurs after a failed WordPress update.
According to this Answer from the WordPress site of StackExchange, you could solve it by doing a manual update:
Download the (last) desired version of WordPress.
Overwrite the current files, except wp-config.php and folder wp-content .
When you access the website, you will request an update of the Database, which you must perform.