Verification Required & Failed

I wanted to install an app but then it brought me to verification required. So i put my password in and then it brings me to my payment method and it says (failed) but i do not understand why if i only have 1 payment method and only 1 subscription active, which is my Apple Music subscription. When i checked to see why it said failed, it didn’t show anything red or mistaken but i noticed that my 3digit code isn’t there, so i putted it and as i thought it was going to work, it brought me back to the verification required again and the same problem. so i am stuck and want to know whats going on.