I think many websites focus heavily on content and backlinks while overlooking technical problems. Issues such as slow loading pages, broken internal links, incorrect redirects, duplicate URLs, indexing errors, missing canonical tags, and poor mobile performance can make it harder for search engines to properly access a website.
For a business website, a technical SEO audit seems like a good starting point because it can reveal problems that are not always visible from the front end.
What technical SEO issue do you see most often on websites?