For anybody using Hugo, you also may be interested in https://lorendb.dev/posts/fixing-hugos-rss-feed/ in which I fix Hugo's feed template to have the entire article as well as a few other niceties.
Edit: that doesn't seem to be importable. Give me a minute and I'll check manually.
Edit 2: I am unable to figure out a fix to the problem, sorry! My feed works fine for me in Tiny Tiny RSS, so I am tempted to say that it's caused by a very strict feed parser.
OK, I found the problem. I hadn't imported the proper RSS namespace thingy to provide the `<dc:creator>` tag. I've fixed that now, so you should be able to read my feed in Thunderbird!