MailBeeMXRecordsDisabledException Class
The exception that is thrown when there was an attempt to request DNS MX records for a non-existent domain or a domain whose SMTP MX servers are not responsive.
Inheritance Hierarchy

Namespace: MailBee.SmtpMail
Assembly: MailBee.NET (in MailBee.NET.dll) Version: 12.4 build 677 for .NET 4.5
public class MailBeeMXRecordsDisabledException : MailBeeDnsRecordsDisabledException

The MailBeeMXRecordsDisabledException type exposes the following members.

Protected methodMailBeeMXRecordsDisabledException
Initializes a new instance of the MailBeeMXRecordsDisabledException class
Public methodEquals
Determines whether the specified object is equal to the current object.
(Inherited from Object.)
Protected methodFinalize
Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.
(Inherited from Object.)
Public methodGetBaseException
When overridden in a derived class, returns the Exception that is the root cause of one or more subsequent exceptions.
(Inherited from Exception.)
Public methodGetHashCode
Serves as the default hash function.
(Inherited from Object.)
Public methodGetObjectData
When overridden in a derived class, sets the SerializationInfo with information about the exception.
(Inherited from Exception.)
Public methodGetType
Gets the runtime type of the current instance.
(Inherited from Exception.)
Protected methodMemberwiseClone
Creates a shallow copy of the current Object.
(Inherited from Object.)
Public methodToString
Creates and returns a string representation of the current exception.
(Inherited from Exception.)
Public propertyData
Gets a collection of key/value pairs that provide additional user-defined information about the exception.
(Inherited from Exception.)
Public propertyDomain
Gets the name of the non-existent or dead host.
(Inherited from MailBeeDnsRecordsDisabledException.)
Public propertyErrorCode
Gets the error code.
(Inherited from MailBeeException.)
Public propertyHelpLink
Gets or sets a link to the help file associated with this exception.
(Inherited from Exception.)
Public propertyHResult
Gets or sets HRESULT, a coded numerical value that is assigned to a specific exception.
(Inherited from Exception.)
Public propertyInnerException
Gets the Exception instance that caused the current exception.
(Inherited from Exception.)
Public propertyMessage
Gets a message that describes the current exception.
(Inherited from Exception.)
Public propertySource
Gets or sets the name of the application or the object that causes the error.
(Inherited from Exception.)
Public propertyStackTrace
Gets a string representation of the immediate frames on the call stack.
(Inherited from Exception.)
Public propertyTargetSite
Gets the method that throws the current exception.
(Inherited from Exception.)
Protected eventSerializeObjectState
Occurs when an exception is serialized to create an exception state object that contains serialized data about the exception.
(Inherited from Exception.)

This exception can be thrown only if DNS caching is enabled (Enabled is true). In this case, MailBee keeps track of all DNS MX lookup requests made and the following attempts to connect to SMTP MX servers designated by the DNS records retrieved during DNS MX lookup. If, for certain domain, all DNS MX records failed (all SMTP MX servers did not respond), MailBee remembers in its DNS cache that this domain is dead and marks the corresponding DNS records in the cache as disabled. All subsequent attempts to connect to this domain will immediately throw this exception without wasting time on waiting for a response from the dead server. The same optimization is performed when non-existent domain is encountered (i.e. the DNS server returned an error).

However, when Timeout interval (by default, 90 minutes since the moment of adding a record into the cache) elapses, MailBee removes such DNS MX records from the cache. It's assumed the failed server may be back during this time, or DNS records may change, etc, so it's worth trying to check the availability of the host in question again.

Note Note
This exception does not refer to the error which occurred just now. It rather occurs to due to past knowledge (acquired during previous send attempts and saved in the cache) that SMTP MX server (which was determined via DNS MX query) could not be contacted or the domain does not exist.
See Also