wp-admin/nav-menus.php error

Hello,

We are using a woocommerce, Enfold theme and also cloudflare. Whenever we make any changes to the menu now, we get this error:

Error 504 Ray ID: 57b07143cf5dd218 ? 2020-03-28 09:49:39 UTC
Gateway time-out

Which is really odd. The changes do seem to work, as soon as we come back into the admin area and Menu, its been changed – but something is going a bit strange. Any ideas would be welcome? Thank you