Google title preview changes into homepage title

I need your help for SEO Press please. Everytime when I want to edit a site, the SEO Option changes his Google snippet preview text (although I filled out the site title out).

How can I edit the title of a site individual, so that the main website title is not appearing on the google snippet preview? Meta description doesn′t change.

I guess since I add the home page title at the theme editor (header.php / head / title) it doesn′t work out.

greetings
Anna