I am unable to login to my Tesco bank mobile app and every time I try to log on this message pops up:

It looks like something's wrong

We can't display your account details. Come back later or try again now. (DDB-01)

I have a credit card account, but then opened a savings account as well which was the point at which this problem started. Strangely I can still log into online banking fine, it's only the mobile app where this happens. I have also called up on the phone and they helped me re-register my online banking but this didn't work. Any help to sort this would be great.