I found it elsewhere, going to the erieinsurancearena website,
clicking on the Alan Jackson event info,
and where it said to Buy Tickets, I entered the same promo code that I saw for the St Louis MO one (the one that the AJ website currently directs Erie buyers to...) It worked for me. It's been years since he's been in Buffalo (2008) so it looks like this will be the closest to me. Up for a road trip!

I was upset the same thing this morning but decided to look around a different way. Hope that still works for you...