I've been using audio conversation in windows messenger
4.7 for XP Pro to chat with my friend. He's using windows
messenger 4.7 on XP Home edition. Both of us are using 56k
dial-up ISP service. Recently all of the sudden we can no
longer use this feature. The error message on my side (i
initiated the conversation) is "The network you are trying
to connect is unavailable. Pls try again later". On his
side the error message is "the voice conversation has
ended". The same error message appeared for Remote
Assistance. However there are no problems for file
transfer. We do not use any third party firewall.

We have ensured that

1) the in-built firewall has been unchecked
2) our ISP service claimed that it's not a problem with
their side.
3) we have gone through the audio wizard setup many times
to no avail.

What could be other reasons or any solutions to this
problem?? Pls help. appreciate it!