This means that the link(s) requested by the advertiser is added in the published article with a tag that doesn’t match what was specified in the briefing. For example, the link is added with a rel=nofollow when the briefing requests a dofollow link.
You need to update your article so that the link has the same attribute as the one requested (note that no tag = dofollow). If you believe the link you have added doesn’t include any incorrect tag or if you have agreed to a change in the type of link with the advertiser, please contact our support team.