How to check if player ID is active in session

I’m trying to create a command that will contact a player but before doing so I would like to check if the playerID is online and if not send an error message.

Current Code: (Simplified code)
server.js

AddEventHander('chatMessage', function(from, name, message)
    local playerID = 2

    -- How to check that the playerID actually exists in the server?
    if (????) then
        TriggerClientEvent('MY:CustomEvent', playerID, from)
    else
        TriggetClientEvent('chatMessage', from, '', {0,0,0}, "No user found."
    end
end)

I’ve tried the below but it doesn’t seem to work.

if (NetworkIsPlayerActive(playerID)

try to check if name match:

if NetworkPlayerGetName(PlayerId()) == TargetName then
--[[ or ]]
if DoesEntityExist(entity) then