Reddit has a new system to autoremove your comments or posts, called CQS

If you have a too low CQS, your posts can get autoremoved, and many subreddits wont even let you post.

Read about it here:

https://www.reddit.com/user/jespernissenseo/comments/1wgwjtn/beware_of_being_in_bad_standing_in_reddit/