various reason
1. are u able to connect to axon machine, just check the connectivity,
2. just check that firewall is not blocking u from registering from axon
3. just check that extension u are using is correctly created in axon,
check user name and password details
4. if above all things are correct then ur mobile registeration time is too be for
axon
also just check that what details are u feeling in
basic config
1. username axon extension
2 password pass of extension
3. proxy server IP of axon server
4 stun server if u use NAT
hope this help
thanks
abhi