Unable to open subdomain one.example.com: This site can’t be reached DNS_PROBE_FINISHED_NXDOMAIN

Symptoms

• Website's subdomain one.example.com cannot be opened with the following error:

  CONFIG_TEXT: This site can’t be reached
  DNS_PROBE_FINISHED_NXDOMAIN

  OR

  CONFIG_TEXT: This site can’t be reached
  ERR_NAME_NOT_RESOLVED

• The main domain example.com is accessible without any issues.

• The DNS checker https://mxtoolbox.com/ shows that DNS record is not published:

  

Cause

Missing DNS record (type A) for subdomain one.example.com.

Resolution

• If DNS zone is managed by DNS server in Plesk:

  1. Log into Plesk UI.

  2. Add record (type A) for the one.example.com subdomain via Plesk > Domains > example.com > DNS Settings > Add Record:

     

  3. Click the OK button.

• If DNS zone is managed by DNS provider:

  Contact DNS provider to create required A record for domain one.example.com.

Additional information

• Troubleshooting website or webmail inaccessibility: Server not found

• myLittleAdmin is unreachable at mssql.example.com: ERR_NAME_NOT_RESOLVED

• Intermittent error on the websites: DNS_PROBE_FINISHED_NXDOMAIN