Micro.blog has size limits for RSS feeds and your legal feed exceeds that limit. It’s too big, so Micro.blog skips it.
The other error is a little harder to debug from the outside. It’s clear that Micro.blog tries communicating with the Twitter API and fails to do so. Do you embed tweets in some of your posts, maybe with a shortcode like {{< tweet user="FooBarBaz" id="1453110110599868411" >}}?