Mcintosh RS100 problem

Recently bought a wireless Mcintosh RS100. Not exactly an audiophile product, but I got a good deal and it actually sounds quite good for its size. 
I followed the instructions, connected to my network and everything is fine. After I turn it off, I am unable to find the speaker on my iPhone. It loses the connection and I have to wipe the setting back to factory default and re-connect from scratch. Usually takes few hours to lose connection, and definitely gone overnight. 
Connection is via wireless router 3g or 5g network, I have reasonable speed 100mgb with time Warner/ Spectrum. I have their latest router. Im pretty sure the problem is not with the Mcintosh. Has anyone  encountered this problem or can venture a guess? I actually have the same exact problem with my Node2, and had to hardwire it to my network.