Sometimes you insert the shortcode into the code, and instead of seeing the final result, you will see the shortcode itself as plain text.
Why does this happen?
This behavior means that you must have inserted the shortcode to the area that doesn’t support WordPress shortcodes. In this case you need to re-insert the InstaLink shortcode into a correct area.
Here you will find a short tutorial that will give you additional information concerning the use of shortcodes. https://elfsight.com/help/what-are-wordpress-shortcodes-and-how-do-i-use-them/