unable to view pages after editing

Hi,
I am unable to view pages from the edit screen. After updating and clicking on View Page, I go to the page but it requests login. After login the following message appears.
Warning! Simple Membership plugin cannot process this login request to prevent you from getting logged out of WP Admin accidentally.

You are logged into the site as an ADMIN user in this browser. First, logout from WP Admin then you will be able to log in as a member.

Alternatively, you can use a different browser (where you are not logged-in as ADMIN) to test the membership login.

Your normal visitors or members will never see this message. This message is ONLY for ADMIN user.

This has only recently been the case. Can you please help.