clarifying note on host field, missing punctuation

applies for example to namecheap

Author: sakaiist

content/pages/configuring-a-custom-domain-for-your-github-pages-site/managing-a-custom-domain-for-your-github-pages-site.md

@@ -101,7 +101,7 @@ To set up an apex domain, such as `example.com`, you must configure a custom dom
 
 {% data reusables.pages.www-and-apex-domain-recommendation %} For more information, see [Configuring a subdomain](#configuring-a-subdomain).
 
-Navigate to your DNS provider and create a `CNAME` record for the `www` subdomain that points to your {% data variables.product.prodname_pages %} default domain. For example, if your site is located at `<user>.github.io`, you should create a `CNAME` record that points `www.example.com` to `<user>.github.io` Similarly, for an organization site located at `<organization>.github.io`, you should create a `CNAME` record that points `www.example.com` to `<organization>.github.io`. Ensure that the `CNAME` record points directly to `<user>.github.io` or `<organization>.github.io` without including the repository name.
+Navigate to your DNS provider and create a `CNAME` record for the `www` subdomain that points to your {% data variables.product.prodname_pages %} default domain. For example, if your site is located at `<user>.github.io`, you should create a `CNAME` record that points `www.example.com` to `<user>.github.io`. (Note some DNS providers only accept the third-level domain (e.g., `www`) rather than the full URL (e.g., `www.example.com`) in the 'Host' field of the record.) Similarly, for an organization site located at `<organization>.github.io`, you should create a `CNAME` record that points `www.example.com` to `<organization>.github.io`. Ensure that the `CNAME` record points directly to `<user>.github.io` or `<organization>.github.io` without including the repository name.
 
 {% data reusables.pages.contact-dns-provider %} {% data reusables.pages.default-domain-information %}