Sometimes when you add a target to Draftboard you'll see that it gets tagged with the status 'Error' - here's why that might be:
There was an error in the profile URL string (e.g. it had "ww" instead of "www" or the last letter got cut off in the copy/paste step)
The target changed their profile URL suffix (e.g. from .../jim-smith-561 to .../the-ultimate-marketer)
The profile URL no longer exists - it's rare, but sometimes it happens. People delete their profiles, retire, or it was an inauthentic profile to begin with and LinkedIn finally found it