I've had that problem occasionally, it is from the router I have, so what I did was unplug it for about a minute, then plug back in. It happens when the power goes out and back on that makes router go "off course". I do this way, to make router go back to normal. I know it's a hassle, and also VP-200 have a test call back features to test if you able to see other side, and to get incoming calls. If anyone don't have that, the Sorenson Test Call Back number is (801) 287-9500.
Hope this helps
Ahhhh....this is something I haven't tried! Thanks...I'll give a go!