Editor showing Undefined

When in cornerstone i am unable to edit anything - I am just seeing the attached screenshot

please advise

Login details attached if needed

Hello @CEG_SA,

Thanks for writing to us.

I checked your site dashboard, you may need to disable ModSecurity or at least whitelist the following URLs in the secure note. Please note that we use the WordPress REST API for saving, and it looks like your web host does not support it. Please ask your web host to support WordPress Rest API or whitelist the URL in the following screenshot.

Thanks