I'm trying to change my seat due to my sons traveling on the same flight. When I tried doing it, I kept getting the below. Clicking OK nothing happens.

I am logged in with my username. Has anybody experienced this? I also tried doing it on mobile but the same thing. Is there any other method I can use to make the change? Would appreciate any tip on how to do it.
Also, strange thing that my wife has auto check in enabled. How do you cancel this? I have requested auto check in at all. Thank you.