This is saying that it can’t connect to that IP to get the erlang image to build with. You can try running fly apps destroy fly-builder-wispy-violet-2739, then running your build again. This gives you a builder on different hardware/network.
The Docker public registry has been very unreliable lately. Network timeouts like that are usually caused by some routing issue between us Docker. We have some workarounds in mind but we haven’t been able to build them yet.
That github actions commit does default to a remote builder. You can try running with --local-only to use your own Docker. It’s very slow in GitHub because there’s no image caching, but it works ok.