Downloading a workflow artifact is refused some machines

Hi all,
I’m having an issue with downloading artifacts that seems to be machine dependent.
Both of them are Raspberry Pi’s that are configured as self-hosted runners in GitHub.
It works fine on one machine but not on the other, where a GitHub server blocks access.

Here is the executed workflow:

This is the log from GH Actions:

==> Workflow: build-workflow.yml
==> Repo: abelikt/thin-edge.io
==> Conclusion: success
==> Branch: continuous_integration
Error: request to https://api.github.com/repos/abelikt/thin-edge.io/actions/workflows/build-workflow.yml/runs?branch=continuous_integration&event=&status=success failed, reason: connect ECONNREFUSED 140.82.121.5:443

It seems to work fine when I fetch the url via curl on the machine where it fails:
curl "https://api.github.com/repos/abelikt/thin-edge.io/actions/workflows/build-workflow.yml/runs?branch=continuous_integration&event=&status=success"

I’m quite puzzled.
Do you have an Idea why the access is blocked?

Thanks, Michael

==> Workflow: build-workflow.yml
==> Repo: abelikt/thin-edge.io
==> Conclusion: success
==> Branch: continuous_integration
Error: request to https://api.github.com/repos/abelikt/thin-edge.io/actions/workflows/build-workflow.yml/runs?branch=continuous_integration&event=&status=success failed, reason: connect ECONNREFUSED 140.82.121.5:443