If you've sent a post to Google My Business and it's not appearing, there could've been two different issues.
1) Your permissions may have been revoked and the post may not have been sent because of this.
2) Your post may contain a word that is deemed inappropriate and therefore wasn't sent out.
To find out whether your post has been rejected due to inappropriate content, log into your Google My Business account. This will show up as a rejected post. Some posts that are rejected due to permissions may not show an error in your Google My Business account.