"No reply to our critical packet"

Hi, so I spent the last little while trying to get Asterisk up and for the most part it works fine. I can make and receive calls. The problem comes for other people.

My Asterisk server is behind a NAT router, however it’s configured to forward all traffic which is not otherwise expected to the box’s IP. I myself am perfectly capable of registering with Asterisk and making calls even when I am using the external IP of the router, so it seems to forward fine. I’m on the same router, though.

Everyone else, on the other hand, can authenticate, but when they try to make calls I see the error “no reply to our critical packet” in the console and they can’t hear anything. The call goes through fine, my extension rings, but the voice doesn’t seem to get through. These people are all behind their own NAT routers.

Anyone have any help here? I’m using X-Lite as a softphone at the moment; when I get this all working I’m going to get actual phones, but for the moment this should work. Would I be better using IAX for the client -> server communications? I think X-Lite only uses SIP.

Help!

X-Lite over the years has given me some grey hairs. I have been very happy with Zoiper.