The only discords I know at this time is NWI community and FHI community. Here the info from below:
NWI Community - https://discord.gg/3VAzam3
FHI Community - https://discord.gg/TT53ndS
there is already a discord for that..
I was kind of getting at having an official one for Sandstorm rather than community-run Discord.
If you are looking for Insurgency Sandstorm Discord with active players please join ISP-GL - https://discordapp.com/invite/8gK4CuF
"ISP-GL European Gaming League" have many veterans from Insurgency source and Day of Infamy game.
Most of us play competetive only, but all players are welcome - we can teach you. We don't care how well you know english, how old are you, how good you are or what mode you are playing. Mostly we are playing between 7pm and 12am Warsaw time. We also own private servers that are used for tournaments and trainings.
By the way did you know that on april 2019 we made the first Insurgency Sandstorm tournament with prizes (https://insurgency-sandstorm.pl/tournaments1/).