The Canon 80D shoe does not trigger triggers constantly

I'm shooting with a practically new Canon 80D. Everything was fine and now my flashes are failing. I'm controlling my Flashpoint 600 with the trigger mounted on the 80D's shoe. For some reason, now it does not fire, when I press the test button on the trigger, it always works. I tried a different trigger from another light and the same. Every once in a while it shoots, so I'm not sure what's happening.