It has nothing to do with your router. You've got a modern router that should simply work. IF you haven't upgraded the router's firmware to their latest level, then do that now.
You provided very little information. Have you altered any settings at all on the OBi?
Look at the back of the OBi. Make sure you have connected the Ethernet cable to the WAN port, not the LAN port. By default, I don't think you can access the OBi's local web page via the WAN port, unless you changed a setting first, so something is fishy here.
Factory reset it: find the reset button, which is under a small bump with a hole in it, on the bottom of the device. Using a paper clip, gently press the button until you feel a click, and hold it for at least 10 seconds, until the power LED flashes. Give it a few minutes to cycle through the reset. Try your call again.
Seriously: if it doesn't work, open a ticket.