First welcome to our humble forum!
as its a taurus 709 and i think about to be discontinued if not already then it might have been sitting on a shelf for a while.
the reason that i mention this is that taurus is known for way over lubricating (or preservative) inside the weapons even in busy model years.
many, many , many stories like yours among these pages.
so long story short i suggest that you get some gunscrubber or something similiar that is presurized, field strip that gun spray the hell out of it in all the nooks and crannies.(especially the firing pin channel area)
let it sit for a while then go anout a normal cleaning process and try it again.
if the weapon doesn't respond then I suggest that you quickly contact Taurus and set up a return I think the time for them paying return shipping to the factory is down to like 90 days now.
hope this helps you.