When I want to send an item link through email regardless of user permissions, I get the same error after submitting the email form, Error 403 missing link.

Can someone help point me toward a solution.

Thank you for your help. This had nothing to do with K2. I was able to duplicate the same issue in the native Joomla article as well. It turned out that our template had overwritten the default mailto.php within the mailto folder, of the template directory. I replaced this with the old default mailto.php file and everything works better than expected.

Thanks for your direction.