NoFollow links are hyperlinks with a rel="nofollow" tag. This attribute tells Google and other crawlers the relationship your website has with the linked URL. This attribute will not impact the destination URL in terms of SEO since no PageRank will be transferred. However, this doesn't mean that they're worthless.
Does the Site Auditor crawl NoFollow links?
Our Site Auditor will crawl all the NoFollow URLs on your site and will flag them if, for example, any of them points to a broken URL.
Although Google used to ignore URLs with a NoFollow attribute in the past, recent changes treat these links as a "hint" rather than as a directive. Therefore, NoFollow links can still impact your website's SEO, and it's recommended to fix any issues that might affect them.