I'm also trying to use the meta tag manager plugin on a site so I can verify in google search console. You can see it here:
The verification meta tag is:
<meta name="google-site-verification" content="z-LkLtc7Hm1yLpQ6ZKgg-99M3X6p1kPcigM-OAOu2oU" />
The site i'm trying to use this on is:
It still won't verify.