Unable to login to online banking app on my iPhone

I am not Mable to log into my online banking app from Santander. The app is there but every time I try to login it says ‘something is wrong we noticed your device can’t connect to this app’ then it tells me to go to settings.

but there is nothing there I can do. What I did notice is in the settings it gives me far fewer options to set compared to my BOA app which is running fine.

many ideas ?

[Re-Titled By Moderator]