I’m experimenting with a change on Micro.blog with how it processes very large RSS feeds, and this has broken some WordPress feeds. Your RSS feed is 400k and has 200+ posts in it. Until I can fix this, I’d suggest limiting your RSS feed in WordPress to only recent posts, like the latest 20 posts. (This limitation also doesn’t apply to JSON Feed if you want to switch to using that.)
Sorry about the trouble! I didn’t realize it was going to affect any WordPress feeds. Making your feed shorter will speed things up too, though.