It's known (from the DNS cache) that the requested domain name does not exist.
MailBee.NET (in MailBee.NET.dll) Version: 12.2.0 build 630 for .NET 4.5
public const int InvalidDomainInCache
Public Const InvalidDomainInCache As Integer
It does not make sense to make DNS MX query regarding the domain name
since the previous attempt to do so produced negative response from the DNS server and this fact was recorded in the DNS cache.
The developer can use Clear
members of DnsCache
class to affect this behavior.