App (green background white logo) states hub unavailable after reinstalling and logging in. I have the C7 model. Even setup a 2g network. Can access hub via IP address just fine.
Platform version 2.3.9.162
Is there a reason you haven't upgraded to 2.5.0 (the current release) or at least 2.4.4 (the previous release if you're afraid of 2.5.0 for any reason)? Your version is almost two years old.
I'm not aware of any specific incompatibilities, but the mobile app has received lots of updates since the platform version you are running, and it's possible this kind of detection is related to one.
That's where I'd start, at least!
Oh, and also make sure your hubs can access the Internet. If you're not trying to be on this version and the hubs just think they're the latest, that's probably why. 
A network reset is an easy trick that may help with that if you don't have any unusual network setups (static IP on the device itself, multiple VLANs, etc.) -- or if you do, making sure that they are, of course, configured correctly.
This resolved the issue. I first noticed that during a network test it couldn’t reach the internet. It was also indicating that my firmware was up to date and that made me realize something was wrong when it didn't match what you told me was the current version.I don't know why or how this happened. I had to re-establish the network by hitting the reset button. It didn't reset when I just powered down. I had to press the reset button. After the reset I was able to connect to the internet. I downloaded the newest firmware and installed it. i'm back up and running now. Ty