Retrieving Server Info

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The IP's to whitelist are here:
https://www.invexgaming.com.au/serverlist.php

This shouldn't be necessary though if the CSGO application is already whitelisted by your firewall.
You can instead try turning on Upnp and QoS on your router as well as generic CSGO ports used to connect to servers (27000-27500).
This may help.

This may be unrelated but am I the only one that re downloads the same sound file every time I join the JB server.

Go into your CSGO files and delete the specific sound file.
Once you rejoin the server, it should download again and fix the bug.
Additionally, its a good idea to verify the integrity of your game cache.