https://www.webtechmantra.com/reasons-about-facebook-error-this-content-isnt-available-right-now/

The URL shortener murl is a free URL redirection service that allows you to create a short Uniform Resource Locator (URL) or Web page address from a long one so that the short version, which is easier to remember and share, can be used instead
murl will maintain the association between the two and will redirect anyone who enters the short URL to the Web page at the long URL