Champion selection bug - Udyr

I bought Udyr like 15 minutes ago. After that, I wanted to try him in game, then I start team builder, select Udyr, and when I wanted to click on "Find group", some pop up message says "INVALID_CHAMP_SELECT". After that, i chcecked my "Profile-Champions-Owned" and Udyr was there. I was wondering what is going on, then I again try to pick Udyr in team builder, and then he was't there, in champions i can choose. I did relog, and try to pick him again, then appeard same message again "INVALID_CHAMP_SELECT", I don't know what is going on, so please somebody help me!