I am trying to add two grandsream Hanytone 486 ATA's to my SIP network. Both of them worked at first, and them when I tried to make some configuration changes, they became nearly bricked. The red light flashes every second. When I plug in the WAN port the link light comes on as well as the activity light (shows activity). Plugging in the LAN port shows link but no activity. Plugging in a phone gets no dialtone and no power to the phone. Pressing the button on the Handytone does nothing.