I have a Nexus 7 tablet that I have used without significant problems for a bit over two years.
Current android version: 6.0.1
Starting yesterday, it started having problems connecting to the internet.
It finds the router, goes through the connection process, finds the IP address,
and then reports "no internet connection".
The first time it happened, I powered off the tablet and restarted it.
The connection came for long enough for me to completed my task,
but the next morning, I was getting the "not internet connection" message.
I also have a Samsung Note 5 and an Kindle Fire that are both working fine.
Looking at the router (Verizon MI424WR) - MI could be M1, shows the IP address as assigned and active.
There is no apparent IP address conflict.
I have "forgotten" the WIFI connection and reestablished it, with no improvement.