Simply speaking, dofollow links are links missing the rel="nofollow" attribute. Such links are followed by search engines and pass PageRank (please note that links can also be restricted from following in bulk via the nofollow tag). While there is nothing wrong with linking to other sites via dofollow links, if you link extensively to irrelevant or low-quality sites, search engines may conclude your site sells links or participates in other link schemes, and it can get penalized.
Please, revise your followed links and make sure they point to high-quality, relevant pages. It's recommended to remove any links to pages of questionable quality or accompany them with rel="nofollow". To add the nofollow attribute to a link, simply write rel="nofollow" within the <a href> tag. For instance: <a rel="nofollow" href="/example.com">Example</a>.