I added member feature to my website and it is working fine for most users. However, some people using Samsung / Huawei default browser told me they couldn’t login. After they typed in username/password and clicked log in, it jumped back to the main page without logging in. When they tried to go to member page, it asked them to log in again. It’s working on most PC browsers though.
Try going through Wix Support first with this problem as it sounds like you have just added the Wix Members Area which Wix Support will help you with.
By the way, I myself use Samsung phones and my website logs in fine on my mobile devices when I go to my own members area and users login.