I do not doubt other people have had success "fixing" with their little fixes- I have to say, absolutely do not work for me. (I obviously did try a lot of things before I tried posting here).
It is getting much much worse and the only thing that 'fixes' the problem is walking downstairs and unplugging the gateway for a minute and replugging in . What is extremely trippy is my father and I (I'm a halfassed adult that lives with my old man, we just have always been close like that I guess.) have the same problem. We bought our Note 10.1 32GB's brand new at BestBuy on Sat in early/mid April. Started fine but then that happened and its been happening but getting much worse. Past two weeks, happening every single night around "bed time". Now it's been happening day and night.
I just resorted to logging into the gateway admin area, changing the SSiD network name, changing the broadcast channel, and the DHCP lease renewal time ( was like 3 weeks I changed it to much less. Now I am not 101% sure this was the right move so feel free to chime in there.).
I am really hating this. When it's 1130 or 12 midnight, I'm tucked in bed, the house is dark and secure, and I'm laying in bed w/ my Note reading the web or watching a vid etc. and suddenly the net stops, and "Authentication Error' comes up, I do NOT WANT to get up , get ready, go downstairs, turn n all the lights, losing my night vision in the process etc, stumble to the router area, unplug the damned thing, let it go, reboot time takes a bit, come upstairs and reverse everything ,get back into bed, etc. etc. Its terrible.
I will report on how the changing of the settings affect everything. (And again- there is NO PROBLEMS with the rest of the house WiFi. 4 Smartphones, 3 laptops, a stray iPad, etc.).