I have an extended deck and I don't get an error about the cards. But whenever I try to start a new match it just cycles the counter for a bit and then comes back saying no opponent found. This has been ongoing since last night. I can't imagine that I've been unable to find an opponent for over 8 hours straight without something actively preventing me.
The Urban Rivals team is made by lovers of all kind of Collectibles Cards Games and Trading Cards Games like: Magic the Gathering, Dominion, Vampire, Yu-Gi-Oh!, Pokemon, Wakfu TCG, Assassin Creed Recollection, Shadow Era, Kard Kombat and Might & Magic Duel of Champions.