Issued calling-receiving calls from ONLY Vonage #s

I have a rather interesting scenario and was wondering if anyone has had similar experiences.

Between myself and family I own 1 Voipo number and 3 vonage numbers. These 4 numbers have been in existence for about three years. Everything worked great until about six months ago and I have experienced the underneath issues since then.

When I call/receive any number (as long as its not a vonage number), the call goes/comes through perfectly.

When I call any ONE of these three vonage #s (All US numbers but geographically located as in- Chicago, London and the last one in India), I hear the phone ring once only and then get a "fast/busy signal". My folks have gotten used to the fact that if the phone rings once and stops ringing its probably me calling. I call back and if they pick the phone , the calls go right through and am able to have a conversation as if nothing were ever wrong. Receiving calls from the Vonage #s is a bit better...it rings several times but more often than not I do not hear the other person or they hear me.

Calling these vonage #s from any other line such as a softphone (from skype) or mobile #s do not show the same issues.


I was wondering is any users have had similar issues and how they got resolved.

Thanks.
Mir


PS>>> I have not yet contacted tech support as they will want to make the calls etc during working hours to check etc but this may not be possible as my folks wont be near their vonage phone during those hours.. However I have the calls in the calls logs.

almost always a port forwarding/firewall issue. read and follow the general troubleshooting steps.

I have a problem with Vonage also. Impossible to have a conversation, calls always get dropped within the first minute. Seems to be incompatible with Voipo?

I call Vonage phones without any trouble. Those calls are really going through the PSTN, so voipo and vonage would not even be aware of what type of system they are talking to.

Again, the problem is likely a port forwarding/firewall issue. Be sure to set a static IP for your ATA, and forward the sip ports to that IP address. Otherwise, your router's firewall may block audio.