On Thursday, June 27, the Refer-a-Friend quest was given a patch for those still experiencing linking issues. The new player window has been changed to 21 days. A veteran needs to send their new player another link and that should resolve your the linking issue. If linking issues continue, please create a Topic in the Help forum. For more information about the Refer-a-Friend quest, please visit: https://www.bungie.net/Referafriend