Updating Apps

This problem is twofold. The other day I was attempting to make a in app purchase. It wouldn’t go through. I believe the message said unable to complete transaction please sign in with your Apple ID and update your billing information. I enter my password on the prompt screen it said verification failed. I tried one more time I thought I entered an extra letter same thing. I was able to sign in by clicking on my Apple ID. I removed my card information and then I re entered my information I thought it correct the problem it didn’t. I decided to click the option of having no method of payment I don’t think I’ll be making any in app purchases in the near future. Every since I had this problem I started having a second problem. I have an app that needs to be updated so I click on the app that needs to be updated it starts the process but one minute into the update I get this message “Tap continue and sign into view billing information “. I enter my password and it says verification failed. I never had this problem before. My questions are why is this happening? How can I fix this problem? Any and all solutions advice and help is greatly appreciated.