I have a Canon 70D, YN-560-TX and two YN-560IV flashes. The YN-560-TX is synced to the flashes and they work when I press the test button on the transmitter, but when I try to fire with the transmitter on camera it doesn't seem to want to fire. I've tried resetting, changing channels, cleaning my hotshoe but nothing seems to work. Please help!
I suspect you are using Liview. In Liveveiw flash sync is disabled if "silent mode 1 or 2" is enabled.
Using a Canon flash will automatically disable "silent mode" but some 3rd party flash units or triggers are not recognized. Go into the Liveview menu to disable it.
Rebel series cameras have no option to disable "silent mode" so it difficult to use a 3rd party nonETTL flash unit or trigger.