Limited functionality

I have booked a ticket and I used a partner airline to accumulate miles rather than using Krisflyer (I find Krisflyer miles have not much value and strict limitation for award travel; I was shocked to find that I need to use approximately 85,000 Krisflyer miles and $765 in taxes and surcharge for an award ticket where as the same ticket costs me on Singapore airlines website $875/- without using any miles). Now my problems begins. My reservation does not show up in the app. I added it using booking reference number and list name. Now it shows up, but it does not let me do anything stating that I need to login but I am already logged in. I tried by logging out and tried again and same problem. I deleted the app, reinstalled and tried and same problem. However, on Singapore airlines website it works, but on my iPhone it does not work. I cant change or assign seat (I can go to their website and change seats there; AND I do not need to login). I tried to add my known traveler number and I do not see it anymore.

I think Singapore air is trying to provide a good app and if their IT department makes little more effort on UX/UI and considering frequently used user scenarios, they may make the app quite useful.

Sam-7779 about Singapore Airlines, v20.5.1