We have two SimpleDNS Plus instances running both 5.2.126. They are set up to resolve non local domains for specified IP addresses. They have been in operation for 3+ years with no real issues and were recently updated to build 126.
We are seeing a lot of 'RCODE 2 - Server Failure' messages for one of the instances. When we do the same look up on the other instance we get the requested data but for the same query on the other we get the 'RCODE 2 - Server Failure'.
It is not happening for all external requests.
Any suggestions on how we can figure out the reason for the server fail responses?