How to fix error 404 on Portfolio pages?

To fix error 404 on post type archive and single posts, Go to Dashboard > Settings > Permalink and once save permalink structure.

• Still facing error 404  – Deactivate all of your 3rd party plugins and only keep activate theme plugins, then again save permalink structure and check your portfolio pages. If still have them same problem, You need to delete your server .htaccess file and try saving permalink again. Finally if still have same problem, you need to contact with your server support.