You're banned, happened 3 days ago
https://lemmy.world/modlog?page=1&userId=5172779
Looks like you got one from 30rock too, that's how I figured it out when it happened to me.
Some communities ban you if you down vote posts but aren't subscribed...
Especially if a mod made the post.
It's incredibly childish, but they do it because they're mad their post got downvoted