Can't purchase with my Discover Card!!

My order of $76 was canceled 2 times due to “technical difficulties” when I used my Discover card. HSN said there must be an issue with my Discover card. I verified with Discover that my account is in excellent standing! Discover card said they showed no signs of attempted charges with HSN. The problem must be with HSN. Very frustrating that I will not be able to use my discover card for future purchases because they will likely be canceled a week later.