Unable to access website hosted in Plesk using URL with WWW: ERR_NAME_NOT_RESOLVE

Symptoms

• Site example.com and/or www.example.com does not work:

  ERR_NAME_NOT_RESOLVED

• (Optional) Domain URL redirects to www.example.com because preferred domain is setup to WWW in Plesk > Domains > example.com > Hosting Settings or a redirect to WWW is defined somewhere in the site code:

  # curl -I example.com
  HTTP/1.1 301 Moved Permanently
  . . .
  Location: http://www.example.com/

Cause

www.example.com does not have the corresponding CNAME or have wrong CNAME record in site's DNS Settings.

Resolution

If DNS is handled by Plesk (if Plesk name servers are responsible for serving site's DNS):

1. Login to Plesk
2. Go to Domains > example.com > DNS Settings > Add record and add CNAME record for www.example.com that will have example.com value:

   www.example.com CNAME example.com

If DNS is handled externally (third-party name server providers are used):

Create CNAME record for www.example.com that will point to example.com on a third-party name servers provider side.

Note: DNS records propagation may take up to 48 hours, so the site may still not resolve after DNS changes.