I am getting the above error when trying to send to a distribution list with around 200 recipients. If we break the distribution list up into groups of about 40 or 50 it works fine. But it refuses to send all at once. I have searched and searched, is there a setting somewhere i can change to enable this?

This sounds close to your issue...adjust connection timeout. http://social.technet.microsoft.com/Forums/en-US/exchangesvrtransport/thread/8b92718e-9428-45a6-be88-e7e3bef855e6 Tim Harrington - Catapult Systems - http://HowDoUC.blogspot.com

Tried changing that setting. It still doesn't work, is there any other settings i can modify to prevent this error?

A 200 member distribution list is not that big. Are you having any network related issues? How long after you send the email until you see this error message? Can you tell me more about your environment (# of exchange servers with roles and SP levels)? Can you run: Get-ReceiveConnector | FL and post the results?Tim Harrington - Catapult Systems - http://HowDoUC.blogspot.com

Network seems fine. We have 2 exchange servers, 1 mailbox and 1 does everything else. We send everything out to a smarthost on the dmz(barracuda spam firewall). Never had any problems until they started trying to send to this list. AuthMechanism : Tls, Integrated, BasicAuth, BasicAuth RequireTLS, ExchangeServer Banner : BinaryMimeEnabled : True Bindings : {:::25, 0.0.0.0:25} ChunkingEnabled : True DefaultDomain : DeliveryStatusNotificationEnabled : True EightBitMimeEnabled : True DomainSecureEnabled : False EnhancedStatusCodesEnabled : True LongAddressesEnabled : False OrarEnabled : False Fqdn : S-EXCHCAS-01.domain.local Comment : Enabled : True ConnectionTimeout : 00:20:00 ConnectionInactivityTimeout : 00:05:00 MessageRateLimit : unlimited MaxInboundConnection : 5000 MaxInboundConnectionPerSource : unlimited MaxInboundConnectionPercentagePerSource : 100 MaxHeaderSize : 64KB MaxHopCount : 30 MaxLocalHopCount : 8 MaxLogonFailures : 3 MaxMessageSize : 30240KB MaxProtocolErrors : 5 MaxRecipientsPerMessage : 5000 PermissionGroups : ExchangeUsers, ExchangeServers, Excha ngeLegacyServers PipeliningEnabled : True ProtocolLoggingLevel : None RemoteIPRanges : {::-ffff:ffff:ffff:ffff:ffff:ffff:fff f:ffff, 0.0.0.0-255.255.255.255} RequireEHLODomain : False RequireTLS : False EnableAuthGSSAPI : False Server : S-EXCHCAS-01 SizeEnabled : EnabledWithoutValue TarpitInterval : 00:00:00 AdminDisplayName : ExchangeVersion : 0.1 (8.0.535.0) Name : Default S-EXCHCAS-01 DistinguishedName : CN=Default S-EXCHCAS-01,CN=SMTP Recei ve Connectors,CN=Protocols,CN=S-EXCHC AS-01,CN=Servers,CN=Exchange Administ rative Group (FYDIBOHF23SPDLT),CN=Adm inistrative Groups,CN=domain,CN=Mi crosoft Exchange,CN=Services,CN=Confi guration,DC=domain,DC=local Identity : S-EXCHCAS-01\Default S-EXCHCAS-01 Guid : 736590ed-b3e5-4c19-873b-6931ca16478f ObjectCategory : domain.local/Configuration/Schema/ ms-Exch-Smtp-Receive-Connector ObjectClass : {top, msExchSmtpReceiveConnector} WhenChanged : 7/6/2010 10:41:43 AM WhenCreated : 4/2/2009 1:14:52 PM OriginatingServer : domaincontroller.domain.local IsValid : True AuthMechanism : Tls, Integrated, BasicAuth, BasicAuth RequireTLS Banner : BinaryMimeEnabled : True Bindings : {:::587, 0.0.0.0:587} ChunkingEnabled : True DefaultDomain : DeliveryStatusNotificationEnabled : True EightBitMimeEnabled : True DomainSecureEnabled : False EnhancedStatusCodesEnabled : True LongAddressesEnabled : False OrarEnabled : False Fqdn : S-EXCHCAS-01.domain.local Comment : Enabled : True ConnectionTimeout : 00:20:00 ConnectionInactivityTimeout : 00:05:00 MessageRateLimit : 600 MaxInboundConnection : 5000 MaxInboundConnectionPerSource : 20 MaxInboundConnectionPercentagePerSource : 2 MaxHeaderSize : 64KB MaxHopCount : 30 MaxLocalHopCount : 8 MaxLogonFailures : 3 MaxMessageSize : 10MB MaxProtocolErrors : 5 MaxRecipientsPerMessage : 200 PermissionGroups : ExchangeUsers PipeliningEnabled : True ProtocolLoggingLevel : None RemoteIPRanges : {::-ffff:ffff:ffff:ffff:ffff:ffff:fff f:ffff, 0.0.0.0-255.255.255.255} RequireEHLODomain : False RequireTLS : False EnableAuthGSSAPI : True Server : S-EXCHCAS-01 SizeEnabled : Enabled TarpitInterval : 00:00:00 AdminDisplayName : ExchangeVersion : 0.1 (8.0.535.0) Name : Client S-EXCHCAS-01 DistinguishedName : CN=Client S-EXCHCAS-01,CN=SMTP Receiv e Connectors,CN=Protocols,CN=S-EXCHCA S-01,CN=Servers,CN=Exchange Administr ative Group (FYDIBOHF23SPDLT),CN=Admi nistrative Groups,CN=domain,CN=Mic rosoft Exchange,CN=Services,CN=Config uration,DC=domain,DC=local Identity : S-EXCHCAS-01\Client S-EXCHCAS-01 Guid : 7d71439c-7499-4471-bb27-dba7aadf3580 ObjectCategory : domain.local/Configuration/Schema/ ms-Exch-Smtp-Receive-Connector ObjectClass : {top, msExchSmtpReceiveConnector} WhenChanged : 7/6/2010 10:41:43 AM WhenCreated : 4/2/2009 1:14:52 PM OriginatingServer : domaincontroller.domain.local IsValid : True AuthMechanism : Tls Banner : BinaryMimeEnabled : True Bindings : {IP:25} ChunkingEnabled : True DefaultDomain : DeliveryStatusNotificationEnabled : True EightBitMimeEnabled : True DomainSecureEnabled : False EnhancedStatusCodesEnabled : True LongAddressesEnabled : False OrarEnabled : False Fqdn : internalmail.domain.com Comment : Enabled : True ConnectionTimeout : 00:20:00 ConnectionInactivityTimeout : 00:05:00 MessageRateLimit : unlimited MaxInboundConnection : 5000 MaxInboundConnectionPerSource : 20 MaxInboundConnectionPercentagePerSource : 2 MaxHeaderSize : 64KB MaxHopCount : 30 MaxLocalHopCount : 8 MaxLogonFailures : 3 MaxMessageSize : 30240KB MaxProtocolErrors : 5 MaxRecipientsPerMessage : 200 PermissionGroups : AnonymousUsers, ExchangeServers, Cust om PipeliningEnabled : True ProtocolLoggingLevel : None RemoteIPRanges : {IP's allowed to send} RequireEHLODomain : False RequireTLS : False EnableAuthGSSAPI : False Server : S-EXCHCAS-01 SizeEnabled : Enabled TarpitInterval : 00:00:00 AdminDisplayName : ExchangeVersion : 0.1 (8.0.535.0) Name : localmail DistinguishedName : CN=localmail,CN=SMTP Receive Connecto rs,CN=Protocols,CN=S-EXCHCAS-01,CN=Se rvers,CN=Exchange Administrative Grou p (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=Domain,CN=Microsoft Exc hange,CN=Services,CN=Configuration,DC =domain,DC=local Identity : S-EXCHCAS-01\localmail Guid : 7afe0eac-4296-45ad-99f2-c2023feb3aa8 ObjectCategory : domain.local/Configuration/Schema/ ms-Exch-Smtp-Receive-Connector ObjectClass : {top, msExchSmtpReceiveConnector} WhenChanged : 7/6/2010 10:41:43 AM WhenCreated : 4/30/2009 9:23:14 AM OriginatingServer : domaincontroller.domain.local IsValid : True