I've been having trouble too and not long ago today I contacted Verizon and they gave me the number to Verizon Up team. I guess I won't need to call if they are going to do the same to me. I have been having this error message since December 19. I was trying to get the 50% off of JBL Tune 120. I hope they can get this fixed for us all because I hate missing these rewards!
I'm having the same problem, and even recently upgraded from an iphone 6 to an iphone se and the problem STILL is happening!!! So new install, new phone even... same problem. Can't use the $5 visa gift cards nor choose the $3 pick a card one.