Help on Posting facebook groups

sometimes its just lazy moderators that aren't approving the posts. you may see new posts from that same group but it could be just from the admin's proxy accounts

Posting on multiple groups with your account may result in spamming. You should carefully check the content you post.

Most likely it's not your accounts—it's Facebook's trust system.
Pending posts usually come from low trust with the group or posting the same pattern across many groups.
The people posting 20–30 times/day usually spread activity across multiple trusted accounts and vary their content.