Have problem viewing seating map on UA.com
 

Booked a trip CDG-ORD-LAX-SYD-SFO-FRA-CDG for which I got all my upgrades confirmed except the ORD-LAX leg.
When I access my itineraries on UAL.com everything shows up however when I want to access the seating map only the Y-class cabin shows up on all sectors and i consequently cannot change my seat assignment in case a better seat becomes available. Anyone knows how to deal with the problem?
Thanks for the input

Go to seatguru.com to find the best/worst seats for the flights, then call the 1K line to reserve the ones you want - and make sure you mention that a .com issue is preventing you from doing it online. (not that anyone at United will take note of it, do anything about it, or care.)