I think I used Safari, because I have all sorts of script and cookie blocking on FireFox (my normal browser). I guess you could try it on the iPhone or an iPad as well. I wish I could be more specific, but I no longer have the option, because it's already been delivered I'm going from memory here.
Did you successfully log in to UPS My Choice? if you're not logged on or have cookies disabled, it might bug you forever. They seem to insist you sign up I did that a year ago and don't remember what was involved (but it was free to register).
Thanks, tried from my iPad and got the same results. Guess I'll know a better status in 24 hours. Hoping by then if the delivery attempt failed it prompts me to choose pickup as an option.