Hi,
According to the messages, heartbeat packets are arriving too late.
I suggest that you run a ping command from the same machine you use to play to your server in parallel and see if there's a spike in latency at the frequency you said (every 60s).

Hello,
I d'ont see any error in the log you provided.
What do you mean by "isn't working" ?

I asked for a roadmap or anything, here is the answer :

Random heroku support guy wrote:Hello,

We don't currently have any plans to support IPv6, to keep up to date with product announcements and new features, please subscribe to our Blog and Changelog

Best,
Tim

There's nothing more I can do on my side.

Thanks for the reply, at least I know you are aware of the situation.

The authentication server runs on Heroku, which doesn't support IPv6 for some reason

Heroku uses AWS, probably they always did. But AWS started to provide IPv6 quite recently, especially on certain of their products.
That ...

Hello,

I'm trying to run a headless server on an IPv6 only machine.
The server stops because of :

0.528 Info HttpSharedState.cpp:44: Downloading https://auth.factorio.com/generate-server-padlock-2
0.654 code:7, 7; Couldn't connect to server

It seems that auth.factorio.com doesn't provide any ...