Login Bug?

Hi

As an admin, I have no problem with login.

I made a test user, login with browser in Incognito mode, no problem.

My subscribers login with websitename.com/wp-login.php, no problem.

My subscribers login with websitename.com/membership-login, the page keep looping asking for login, and sometimes sees other user’s profile

Any advice on how to solve this issue? Temporarily I make them login via websitename.com/wp-login.php but in a long run want them to login via websitename.com/membership-login.

Thank you