Group is selected to grant access, but aren’t able to edit

Hello, for some reason, after installing the plugin and creating the User Group, then selecting the users to be a part of that group; when on the page itself, it doesn’t allow those in that group access to edit the page, even when the group is selected to grant access. The only way to grant access to a page in the backend to edit is if they are selected as the “Author” of that page. I need to have access for 2 different people to edit the same page. Any ideas why it would be doing this? Please advise. Thank you!

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