Server did not respond to register error

[vatsal]

I keep on getting the following error message in the logs in both Express Talk and IVM attendent v4.01. (both purchased software)

 

FOR TALK

Server T0114-6 did not respond to register (sip:101@T0114-6)

check server for that line

 

FOR IVM

Server t0114-6 did not respond to register (sip:199@t0114-6)

check server for that line

 

I've checked the settings and everything seems to be correct. So I am at loss as to what to do next

 

settings for Axon, IVM and Talk

use uPNP - ticked

use STUN - ticked

settings

server 1 stun.voipbuster.com

server 2 stun01.sipphone.com

 

Thanks

 

Vatsal