Seems commenting following lines in newsfeed.js does the trick but it removes completely “Loading …” status when one could still use it.

Would you accept if I push a modification to add another configuration parameter to this module to manage this behaviour ?

I prefer to ask before risking refusal …

// wrapper.innerHTML = this.translate(“LOADING”);
// wrapper.className = “small dimmed”;

Looks like a temporary error to me. Either your pi has some trouble accessing the internet or the server running at 151.101.120.162 is currently busy/down for maintenance/…
I’d retry some time later

I can confirm now my problem came from proxy configuration, module just didn’t handle error response which was not feed formatted.