Comment on WordPress Custom Nav Menu by SEO Dave.

WordPress Drop Down Menu The WordPress Custom Menu is unlikely to cause a home page 404 error page.

Not seen a home page error before.

Have you set a “A static page (select below)” under Settings >> Reading?

If so does the static page exist? Not sure what would happen if a page was selected and later deleted, would guess what you are seeing.

Try setting to “Your latest posts”.

Beyond the above I’ve never tested the front page setting without setting permalinks (Settings >> Permalinks), so I’d check that next.

Then there’s the obvious disable all plugins and see what happens :-)

David