What "external link within ProConnect" are you referring to?  If you're referring to links to articles in this Community, there's no solution to that because Intuit didn't care to update those links or properly migrate the articles when they moved to this current platform despite having been informed of that being a problem umpteen million times before and after the migration.

In case you have any specific question, you may like to open a new thread.  Otherwise, post the particular links you have problem with and tag the Community Managers so that they can help escalate.