Cannot update or install some apps on iPad: Enter a valid phone number

Hi,

So I was trying to update one of my apps today on my iPad and I got something a little bit different... As I clicked on the Update button next to the app, I got a message saying “If you have an Apple ID, sign in with it here.” And with a box underneath to type in my Apple ID.

I had never seen this password alert before when I was installing or updating apps. So I just entered my password and hit the Download button as like I would do all the time. So then did the update for the app download? Nope! Instead I got an alert telling me to Open the Settings app to continue signing in with my other email associated with my Apple ID that was not used to download or update apps.

So then I tapped on the Settings button on the alert and then redirected me to the Settings app. I was

then on the Apple ID page and got YET ANOTHER alert message! This time it was telling me that the Verification failed and I would have to enter a valid phone number.

So I then clicked on the OK button on the alert and then nothing came up on screen telling me about entering a valid phone number. I tried looking everywhere in Settings about the phone number and couldn’t find anything. I experimented with other updates and apps. I can no longer update some apps until this problem has been fixed. This doesn’t apply to all apps as some of them update and some of them lead to this particular issue. Same goes for installing new apps. I can install apps like YouTube, but when I install the Apple Support app it leads to this issue above. Any suggestions to fix the problem would be greatly appreciated!

Thanks!