Master Cards keep declining the cc_validation in my live store!!! Please help!

[ACE99]

We've been doing business online for 3 years with OSC, and recently we've had problems with Mastercards going through our checkout. For some reason certain cc numbers keep declining. How can I fix this? We use authorize.net and the cards go through fine using their online terminal. Something is messed up with our cc_validation class, but I've never changed it! How can I fix this??

[user99999999]

Here is some help.

 

http://www.oscommerce.com/forums/index.php?sho...l=cc_validation