Vonage VT2142 installation in Mumbai Sify

Hi,

I am trying to install Vonage.

And I am getting following message :
"this telephone line can not register to vonage network"

According to my opinion Internet is working perfectly. There must be something wrong on Vonage side. If you guys can help me either way it would be great. Below are the technical details.

Indicators on VT2142 vonage device:
Internet light blinking green
Ethernet light steady green
Power light : blinks twice in green

I am in Mumbai, India and using Sify ISP which uses DSL technology.
Following is the Internet configuration :

DSL Wire from Sify ISP -> VT2142 -> Laptop

Laptop is getting internet and on VT2142 status page it shows connected.


Details :

Speed test statistics
---------------------
Download speed: 254768 bps
Upload speed: 252984 bps
Quality of service: 93 %
Download test type: socket
Upload test type: socket
Maximum download pause: 205 ms
Average download pause: 104 ms
Minimum round trip time to server: 287 ms
Average round trip time to server: 473 ms

VoIP test statistics
--------------------
Jitter: you --> server: 2.3 ms
Jitter: server --> you: 0.0 ms
Packet loss: you --> server: 0.0 %
Packet loss: server --> you: 100.0 %
Packet discards: 0.0 %
Packets out of order: 0.0 %
Number of supported VoIP lines: 4
Estimated MOS score: 3.5

As usual Vonage as well as Sify customer service did not help much.

Please help me here.

Thanks,
Rahul