I have been having this problem the last couple of weeks, but it has only happened after sending or receiving faxes. I have been able to send and receive faxes in the past. I have a 4 in 1 wireless printer. I believe I have the printer connected to the surge protector and the adapter box for the grandstream is also connected to the surge protector. Then a phone wire goes from the surge protector to a wall outlet that connects to the phone handset in another room. Confusing, I know, but has been working until recently.