I have the Samsung Galaxy Note 4 from Verizon and have run into problems with messages and WiFi. Sometimes when I turn off WiFi, I find that I can't turn it back on. If I try to go into WiFi from settings, the phone freezes for 5 seconds, and directs me to a blank WiFi settings page with the "on" slider grayed out on top.
I've also had problems where I can't send/receive messages even though I clearly have service (calls come through).
Restarting the device is the only thing that seems to work.
Also, maybe unrelated, but airplane mode takes almost 10 seconds to turn on. Is this normal?