During transfer of zone %1 from master at %2, the DNS server received a resource record (RR) for domain node %3 at which ...

During transfer of zone %1 from master at %2, the DNS server received a resource record (RR) for domain node %3 at which an CNAME (alias) RR was already received.  When used, the CNAME RR must be the only record for its domain name.  The CNAME RR for %3 will be ignored.