Check DNS says no record, or points somewhere else
What each message means and the fix.
"No record found yet." Either the record isn't saved, or it hasn't spread across the internet yet. Wait 10 to 30 minutes and click Check DNS again. Still nothing after 2 hours? Double-check the Name is exactly blog (not blog.yourdomain.com, unless your registrar asks for the full name) and the Value is exactly sites.updatemyseo.com with no spaces.
"blog.yourdomain.com points to something else." There is already a CNAME on blog pointing to another service. Edit that record's value to sites.updatemyseo.com, or delete it and add ours.
"has an A record." An older record of a different type is sitting on blog. Delete the A record for blog, then add the CNAME.
It verified but the page won't load. Give it up to 15 minutes; the security certificate is being issued. If it's still down after that, email us.
I'd rather not do this myself. Click Do it with me on a 5-minute call on the Site & publishing page. Screen share, we type, done.