I attempted to do an upgrade for my dad and his significant other on a flight that shows J class as being available for upgrade, but I get this error when I attempt to process the upgrade.

"We're sorry, we're not able to process your eUpgrade request at this moment. Please ensure you are within your upgrade booking window."

The flight is 9 days from now so they are within the eUpgrade window (E50K), so I cannot figure out why this is happening! I was able to waitlist them for the flights down, but that error message keeps coming up when I try to confirm them in J class for the flights back home.