If you cannot publish a scenario or other entity settings for the first time, there can be several causes. Please check the different possible causes below.

Another entity is being published for the first time

A message is shown stating that a publishing process for another entity is still running. 
You can run only one first-time entity publish at a time (for a first-time publish). Wait about five to ten minutes and try again.

You do not have the Power Automate license 

Another cause can be that you do not have the Power Automate license. Without this license, you can update existing scenarios and other entity settings, but you cannot publish an entity for the first time.