Nexus5 not connecting to only my wifi network
This question thread has been very helpful -- I too developed the same problem, which started after 2 events:  being away from my home for 2 months, and also receiving the latest Android 4 updates (over-the-air) -- across 3 Android devices: my HTC one, my Nexus 7, and an Alcatel Fierce. All have Android 4+

After hours inside the router's setup panel, testing, I solved it with your help, Izzy. But it wasn't the channel... It was the GHz setting!

The home router was set for 5ghz. everything always worked fine, until the latest Android updates. Now, none will work; all give the same famous message: Not in Range. This is absolutely erroneous, since all PCs/Macs in the house could use the Wifi network just fine. (I won't even mention the brand of router since it doesn't matter.)

To solve the problem, I tried eliminating most variables, in both the router and the android devices:


SSID on/off -- didn't matter; not in range;
Channel changing -- no effect; still not in range;
restarting router and phones and tablets -- no luck;
toggling WIFI optimizations/power saving/dhcp-vs-static -- no luck


What DID work was changing the broadcast channel from 5ghz back to the more crowded 2.4 GHz.  Success.
And rats, I'd rather be using the 5GHz.

So I conclude that this is an Android 4+ software bug. (Phone hardware, you think? How could all three devices have a problem with 5ghz, when they ALL worked fine before on this same network, before joining other networks fine?) There's something wrong with the software such that once they join a 5GHz wifi network, then connect later to another network (cafe hotspot, other network, etc.), they lose the ability to "see" the network they first connected to.