I don't think the issue is because of Etisalat, the mentioned port (6600) is not blocked! What are you doing is testing the port forwarding of 6600 on your own pc, which will be always blocked. I've checked using the same website but I've entered the host IP as the BNS authentication server (126.96.36.199) and it was open.
Also I used the PsPing to ping the Auth server on port 6600 and below is the result of this ping:
PsPing v2.10 - PsPing - ping, latency, bandwidth measurement utility
Copyright (C) 2012-2016 Mark Russinovich
Sysinternals - www.sysinternals.com
TCP connect to 188.8.131.52:6600:
5 iterations (warmup 1) ping test:
Connecting to 184.108.40.206:6600 (warmup): from 192.168.*.*:53420: 250.02ms
Connecting to 220.127.116.11:6600: from 192.168.*.*:53421: 241.71ms
Connecting to 18.104.22.168:6600: from 192.168.*.*:53423: 248.16ms
Connecting to 22.214.171.124:6600: from 192.168.*.*:53424: 242.67ms
Connecting to 126.96.36.199:6600: from 192.168.*.*:53426: 245.24ms
TCP connect statistics for 188.8.131.52:6600:
Sent = 4, Received = 4, Lost = 0 (0% loss),
Minimum = 241.71ms, Maximum = 248.16ms, Average = 244.44ms
From above I've received a response from the mentioned server, which clearly indicate that the port is not blocked from Etisalat. And this will lead us that the issue is at BNS side!
Where we, as UAE players, deserver an official response from BNS about this issue, or they need to return what we spent on this game if they are not willing to help or explain.