Hello Robert, typically with that error message there will be an error highlight at the top telling you what is missing.  Groups aren't required to publish, but you do have to select topic, Public/Members Only, etc.

The error message tells you what you missed, typically it is the drop down menu for categoty/topic.

Your have received some good advice. Good luck!

easier said than done look at what the error message is and then scroll down to find the problem... my take is use your hands to pull down the post to see what options are available to you Endre

Robert, I hope you got it right and able to publish your post.

Keep trying, Robert. You will figure it out. AR Support and members here will provide help if possible.

Looks like ActiveRain Member Support has this one covered. 

Look below your post, there are some required fields to choose from before it will post.