If you encounter an error message "The link you followed has expired. Please try again"  after installing the BuddyBoss plugin, this issue happens on new WordPress sites because of file upload size. 

You may follow this article and use any of the methods to increase the upload file size. Once you have increased the upload file size limit, try again uploading the BuddyBoss plugin and it should work fine

Reference: https://buddybosswp.freshdesk.com/a/tickets/259742