Check the base of the plant and see if there's what looks like sawdust.
If so - it's a squash vine borer.

The plant can be saved - depending upon how much they have eaten.
I had that problem with some pumpkins i grew a couple of years ago.

They hatch in the dirt and eat their way into the stem - about an inch above the soil line. They proceed to eat their way up inside the stem - basically hollowing it out.

**WARNING*** This is a gross - but necessary!

You'll have to take a sharp knife or razor blade and cut the stem lengthwise.
You'll spot them inside the hollow stem.
Take a pair of tweezers, grab the little buggers and pull them out.
They are little white wormy things with a brown head. About an inch long.

Keep on cutting & pulling until you've got them all.
I pulled four out of one plant and three out of another.
You can stop cutting when you've reached a point where the stem is solid.
If they've gotten too far up, you may not be able to save the plant. Mine were about 3 inches up. Once I got them all. I tied some twine around the cut stem to hold it together & hoped for the best. I guess it was OK because the plant didn't die & I got a couple of pumpkins from it.

I was pretty grossed out when I started pulling them out. YUCKY! By the 3rd one, I was more pissed than grossed.
I was like, "How DARE you eat MY plant?!?!?"
LOL!

I did some reading on the site and read that it could be pollinating problem. If you don't pollinat in a short time the flower will die and that is what is happening. I am also getting all females, plus they are in a very hard place to pollinate. I also read it can take up to 40 times of pollinating to do the job right and if you don't do it right they will die before you can produce good fruit. This is looking a little hard for me to do in the house.

I don't think it is bugs. I have looked just to be safe. But this is in my house not anywhere outside or even close.
I am coming to grips with tearing it down if I can't do this pollinating right and grow something else. The big thing is to have food to eat. And so far I can't make enough.