I have a small, Simple Active Directory domain set up in AWS using their Directory Service. It's been running fine for a year now. However, this morning, certain DNS queries that run through the domain fail mysteriously.
C:\>nslookup merrimack.com
Server: AWS-68AE5FCF56.xxx.yyy.com
Address: 10.50.11.113
DNS request timed out.
timeout was 2 seconds.
*** Request to AWS-68AE5FCF56.xxx.yyy.com timed-out
However, if I ask Google, it gives me the right answer immediately:
C:\>nslookup merrimack.com 8.8.8.8
Server: google-public-dns-a.google.com
Address: 8.8.8.8
Non-authoritative answer:
Name: merrimack.com
Address: 166.78.30.154
This worked fine yesterday, and as I alluded, for a year prior. All servers joined to this AD domain have the same results, and other queries than to this one domain name seem fine.
C:\>nslookup pfizer.com
Server: AWS-68AE5FCF56.xxx.yyy.com
Address: 10.50.11.113
Non-authoritative answer:
Name: pfizer.com
Address: 184.73.156.141
I am not a very experienced domain operator. How might I diagnose or resolve this error?
Minor edit: the AWS console doesn't show anything wrong with the domain, and all other services (authentication, etc) seem to be working fine.