It is possible that a blank "A" record in the DNS zone file is missing. Please ensure that following record should be present in your DNS zone file:
- Record Type: A (or @)
- Record name: <keep it blank>
- Record Data: 127.0.0.1 (IP address of your server where web-contents of your website resides)
Once you add this record to your DNS provider's panel, allow 24-48 hours to propagate it across the globe.