Error – "You do not have permission to view drafts"

I am suddenly getting the above error when I try to Preview changes to wordpress pages.

I am the administrator and the site has been active since March or April and I’ve never had this problem. It just suddenly began happening since my last login, which was a few days ago.

I have made no technical change to the site at all.

In fact, I can not access the page at all. I can edit it but I can not navigate to the page to preview or visit the live page.

The page is protected content under a membership management plugin we use called WishList Member. So when I try to visit the page, it redirects me to a predifined “Members Access Only” page, even when I’m logged in.

Need help, as the page in question is the main page for our subscribers and though I’m not certain, they may not be able to access the page either.