myLittleAdmin page is not opening on mssql.example.com. One of the following errors is shown in a browser:
mssql.example.com cannot be resolved:
C:\> nslookup mssql.example.com 22.214.171.124
*** google-public-dns-a.google.com can't find mssql.example.com: Non-existent domain
The DNS zone example.com is hosted on an external DNS servers.
There is no A record for mssql.example.com on the external DNS server.
Add the A record for mssql.example.com on the external DNS server, which is responsible for the zone example.com.