Look at your cards, if it has a pill corss out, it can't play in the ELO.
or you have too many stars over 25, go to your deck and get rid some
Just Click Remove From deck and then save the deck as a pre-set. Possibly save 2 so that the ones you plan on using in tournaments don't get all the extra cards you acquire mixed in with them.
I thing you have now all cards in your deck check your deck mayby you have some doubels in you cant play with doubels in tourny room or you have to much stars so you can play only fight typ 2
Click on my deck so you see in wich fight typ you can play
That's easy bro,,,,, if u barely got ur cards then is not gonna let u play in tourny rooms cuz u got too many low level cards,,, that's when it shows u the lost warehouse room,,,, u can level up ur cards n then chekitout again n it should work,,,, if not then sell ur cards n buy the same ones max,,,,, alot of people buy cards with 0exp. n level them up n then sell them,,, but if u want just level them up urself