My Iphone 4S no longer connects to wifi networks

My smart-phone is not so smart and hasn't been since the last OS update.

I've tried to decipher where the problem is and it appears it occurs on networks where there is a "pop-up" asking you your log-in credentials (ie. airport hotspots, cable hotspots, hotels, etc.). The phone is not automatically finding and asking to join those networks. If I manually select the network in settings I get the unhelpful message that the phone is "unable to connect" to the named network

The forums suggest resetting the network but that's not an option in these cases.

I've tried resetting the phone, forgetting the network and trying again. etc. etc. but the problem persists. I thought the update to the update would fix it, but so far there is no change. I've tried manually connecting but that requires that I know the network password, protocol, etc and in most cases I don't.

It was a major problem on vacation, where I did not have cell service. The hotel had free wifi but the iphone 4S was unable to connect. (My friend's Android did, for what it's worth, and so did my ipad).

I'm one frustrated Apple consumer.