meta name google site verification

Hello, I am trying to add meta name google-site-verification to my site. i am using the ColorWay theme and trying to edit the ColorWay: Header (header.php), so looks like this:

[Code moderated as per the Forum Rules. Please use the pastebin]

but every time i try to update file it loads a ‘Error 404’ page and fails to verify on my webmater central page.

Any ideas why it is doing this?