How to Remove W3C Errors From Theme

Have you modified the theme? If not try deactivating all your plugins. If it still remains that there are errors then you have to look into the content you put into posts, the posts that appear on the home page since you’re validating that page.

The theme itself has no issue https://validator.w3.org/check?uri=http%3A%2F%2Fwp-themes.com%2Fhueman%2F&charset=%28detect+automatically%29&doctype=Inline&group=0

I have the same problem, duplicated tag becaus tag cloud in sidebar and syntax errors for releated videos….