After subscriber logs in, goes to dashboard not the right restricted page

Having so much trouble with the restricted page on my website. What I want is if someone clicks on Resources in menu, a login form comes up for them to complete before they can access that page. And I want people to be able to log in on log in page without any error messages.

I’ve been trying to deactivate plugins to see if that helps.
Findings so far:

When I have the bluehost plugin activated, I get:
When I click on log in page, the login form appears, I complete it and get sent immediately to some kind of WordPress dashboard. Then if I click the back button on the browser, I get into the log in page which say ‘You are currently logged in as xxx’, and I can access the restricted part of website as logged in user.
When I click on ‘resources’ in menu, the login form appears, I complete it and get sent immediately to ‘Sorry, you are not allowed to access this page’ message. Then if I click the back button on the browser, I get into the resources page fine as logged in user.

When I have the bluehost plugin DEactivated, I get the same from log in page.
When I click on ‘resources’ in menu, I can log in and proceed to Resources page in the normal way.

No other plugins seem to have any effect.

So if I keep Bluehost plugin deactivated (hopefully that won’t matter?) users can access resources, but there’s an alarming error message after they complete the login form. Any ideas what else I can try in order to solve this?

Many thanks for any help.

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