It's going to be one of two things:
 • No block has been confirmed since
 • The fee set was too low.

It looks like you have a transaction fee of 10000 satoshi and a size of ~330 bytes so maybe that's the problem (though that does seem quite a high fee).

The was a block only 8 minutes ago so that might not be the problem (sadly, you'll just have to wait for it to confirm, there may just be more transactions with a higher fee than you curently).