I can't get Simple Voice Chat to work

I recently installed simple voice chat on my MineOS server, but the mod (in-game) shows the disconnected plug icon (meaning it is not connected), I have forwarded the port on my router but Simple Voice Chat just doesn’t want to work. How do I check firewall settings in MineOS to see if MineOS is blocking the Voice Chat port?
(I am using MineOS on a TrueNAS server)