Had the same issue earlier in the week, and did the same thing - delete the app and reinstall, and 0 trips loaded. I added some manually, but for a couple I got an error, didn't matter if using PNR or ticket number; meanwhile the website showed it just fine. Then suddenly yesterday all is OK again - so, give it another 48h or so and see if it corrects.

Of course there are still the "regular" issues with some of the most basic things - slow loading, unable to refresh information after the app has been in background for a few minutes, every f*n time when tapping to open a specific leg seatmap it jumps to the first flight of an itinerary. This last one drives me insane as a lot of my trips have 6+ legs - I have messed up seat assignment becasue of it several times. I also have an issue where I cannot added boarding passes for flights originating ex-US to my phone wallet - its been like this for almost a year. It's beyond pathetic they cannot seem their pos app fixed.