While trying to set up Facebook “messages” ad that will have a “chat i whatsapp” CTA button, I encountered the error below :
Promoted Post Caption is Not an Url: The post you are trying to promote (post ID:) has a caption which is not an URL - Fixed!
Well, I fixed it by ensuring I edit the content in the "short’description field everytime the error comes up.
I did not enter any URL in the text field.
I hope this helps.