If you've sent a post to Google My Business and it's not appearing, there could've been a few different errors.
1) Your permissions may have been revoked and the post may not have been sent because of this.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.
3) Your business may belong to a category like hotels that is not eligible for posting.
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.
You can also find out whether your business is eligible for posting by viewing your Social Error Log. If your business is not eligible for posting, an error message will appear that states "Post error: Creating/Updating a local post is not authorized for this location."
This error means that your business is in one of those categories that is not eligible for posting. For more information, please take a look at Google's advertiser forums.