Today we installed the fiveM server on a dedicated windows server. Everything is working so far, except for the port forwarding.
When we tried to connect on our LAN with the local ip of the server everything was fine. However when we tried to connect to the server using the static ip, no server could be found by the client.
So we checked if the port was open by using canyouseeme.org and it was.
When we looked in the console on the server it was saying that it was constantly sending a heartbeat to live-internal.fivem.net:30110.
Here is a picture from the rule in the firewall: