When I tap payment and shipping nothing pops up, why is that?

I was trying to subscribe to a subscription when suddenly it said verification was required and then it goes to a blank page and says cannot connect. When I try to add my debit card again, it says payment declined and it send me to a page to add my Apple ID password, but when I add it constantly loops. Then I try to delete my payment methods and it won’t let me so when I go to the Settings and click on payment and shipping it won’t let me load in.