DNSE-792 — Information about domain contains no glue record
Proxy cannot find information about addresses of the nameserver printed. Possible reasons:
Missing the glue records in parent domain server answer.
Loop of two or more nameservers referring each to other.
Expiring of address information from the cache.
Request is replied with ServFail response code and the domain is invalidated so that next time the query will be started from the parent domain.