Originally Posted by braslvr
I'm zero for 4 in my attemps to use the online feature. All I get is "Error- system is unavailable at this time, please try later". I've "tried later" at least 30 times to no avail.
I found that this message will always occur if you have any non-UA-operated flights in your itinerary, for example a 4 digit flight number due to a CRJ aircraft operated by SkyWest, etc. Keep this in mind when you book if your plan is for someone else to sponsor the upgrade.
