I had the same thing happen to me too. But was about a week ago and I believe it took about ten tries to one person. Another five tries to get another. Needless to say, I didn't place high in the DT.
I stopped playin Dts because of it, i won a dt one time and lost out on about 6 minutes lol could you imagine what woulda happened if i got those minutes!? also what i do is try twice, if it doesn't work leave and rejoin the room
If the retry doesn't work on one try, I won't retry again, go down and hit the refresh button and then the Fight Now button up top. Usually gets me another opponent.
In DM, if there is an odd number of players, there is a good chance you might not be able to find an opponent, considering everyone else is locked in matches. There are a ton of DM rooms and players do get spread out.