Hi Leo,
Please update your Wordpress to the latest version as well (5.3.2 as of this writing). Your current WP version is slightly behind (5.1.4).
Updating WordPress
Remember to clear all your caching features (plugin, server-side, CDN, and browser’s cache) after updating so that the code from the latest release is always in use. This will help you to avoid any potential errors.
Another thing that you need to update is your PHP version. Your current PHP version is 5.3.28, while the Wordpress recommends 7.3 or greater.
Wordpress Requirements
Please contact your hosting support on how to update your PHP version effectively.
Let us know how it goes,
Cheers!