I had the same issue ( among other things). It would connect to the iPad just fine but not my android phone.
Basically it is not a assigning the android phone anew Ip address to communicate with the control unit. This is something that should have been sorted out before releasing the product.
I spent a few hours on the phone with Hayward tech support, was told they would get back to me the next day... that was 5 days ago.
It also didn't pick up the fine sand or clean the transition of my pool so I returned it and ordered a M600 today.
I did a full detailed review of the 650 here complete with video.
Hello, This is my first review and I tried to make it as detailed and fair as possible along with supporting videos. There were things I really liked about the AquaVac 650 and some I did not. Hopefully it will give anyone looking for an AquaVac 650 a good indication if this is the right...
www.troublefreepool.com