RSS Feed Broken?

[Nigel Horne]

The feed http://www.cpantesters.org/author/N/NHORNE-nopass.rss doesn't 
work any more in Thunderbird, and indeed W3C gives lots of "pubDate must 
be an RFC-822 date-time", for example here:

<pubDate>Tue, 20 Jun 2017 01:19:52 UTC</pubDate>
Has something changed?  Or perhaps it's something else that's broken it.

-Nigel