Our single-site plugin may only be used on one domain. The Yoast subscription verification does not look at the HTTP/HTTPS and www/non-www when checking for activation status. However, subfolders and subdomains are used for the verification check. MyYoast treats the following standard URL formats as the same single domain: - http://example.com - https://example.com - http://www.example.com - https://www.example.com MyYoast treats the following subfolder URL formats as the same single domain: - http://example.com/subfolder - https://example.com/subfolder - http://www.example.com/subfolder - https://www.example.com/subfolder MyYoast treats the following subdomain URL formats as the same single domain: - http://subdomain.example.com - https://subdomain.example.com - http://www.subdomain.example.com - https://www.subdomain.example.com