YunaPRO shows Invalid Post URL notification. What does it mean?

It means that the Post’s link is not accepted by YunaPRO. 

To get the correct post link, go to the post and click on the date. For reference, the post link in the following screenshot is https://www.facebook.com/groups/yunapro/posts/818388460432730/ (there is the term 'Posts’ in the link).

After clicking on the Date, please copy that link and use it with YunaPRO.