Failed to load resource

Hello,

I installed your plugin “Ultimate Before After Image Slider & Gallery – BEAF” on my site.

The thing is, when I try to add a new slide, the page goes blank and I get this error in the console:

“Failed to load resource: the server responded with a status of 403 (Forbidden)”.

For this URL:
https://prodentalstudio.com.au/wp-json/wp/v2/types/bafg?context=edit&_locale=user

The message: “Cannot view post type.”

Could you help me solve this?

Thanks in advance

The page I need help with: [log in to see the link]