redeem gift card in apple store only show blank white scr

Hi, i had the same problem 2 days ago. I gifted my wife a gift card but she could not redeem it on her ipad, she also tried it on her iphone but got the same screen as you. I contacted apple support and they told me to use a mac or do it online, and guess what... it worked!

HOPE THIS HELPS: Redeem a gift card on your computer

1. Find the 16-digit code on the back of the card.
2. On your Mac, open the App Store.
3. Click your name or the sign-in button. 
4. Click "Redeem Gift Card."
5. 
6. 
   
7. Click "Use Camera" and follow the instructions on the screen. 

Can't redeem your gift card?

Using a Windows PC?

If you're using a PC, redeem your gift card in iTunes. From the menu bar at the top of the iTunes window, choose Account, then choose Redeem, then sign in and follow the instructions on the screen.

Redeem a gift card on your Android device

1. Find the 16-digit code on the back of the card.
2. Open the Apple Music app.
3. Tap the menu button , then tap Account.
4. Tap "Redeem Gift Card or Code."
5. Enter the 16-digit code. Then tap Redeem.

Can't redeem your gift card?