Hey Susan, I have the Prime so the smaller version of yours, are you trying to connect directly to the wifi on the light?
There is a serial number on the light that correspond to the wifi signal the light is putting out so need to make sure you're connected to the master light if that's how you're running things.
On my prime there is a button you can hold this down for 3 seconds to reset the wifi. Had to do it once on my prime and i'd think the hydra would be the same. Just read theres a factory reset if you hold it down for 10 seconds as well if all else fails