I run a small domain, low volume email, no marketing. Messages are bouncing immediately when sent to one domain. No problems sending email to any other domain; recipient domain reports no problems with other senders; problem occurs with any sender in my domain. We’re not on any blacklists that I can see. Our email volume is too low for any reputation reports that I’ve looked up.
We’re getting correct DNS for the recipient MX. Recipient says nothing showing from us in their logs. They’re running Office365. I’m not seeing outbound messages in our firewall logs either, and the bounce message appearing pretty instantaneously suggests something on our side of things. Bounce occurs the same whether the McAfee services are running on the server or not, including a mention of McAfeeTxRoutingAgent in the Exchange tracking log.
Appreciate any insight. A sample message tracking entry follows, sanitized info in [square brackets]:
RunspaceId : ac30d4d5-8727-4634-8938-6af37374ed54
Timestamp : 12/18/2019 3:17:54 PM
ClientIp : [MyExchangeserverInternalIP]
ClientHostname : [MyExchangeserverName]
ServerIp : [RecipientServerExternalIP]
ServerHostname : [RecipientServerName]
SourceContext :
ConnectorId : [MyServer] to Internet
Source : SMTP
EventId : FAIL
InternalMessageId : 41175851466766
MessageId : <873CD1E2-E01C-4BAF-BFA9-07AF323C98C5@[MyDomain]>
Recipients : {[RecipientEmail]}
RecipientStatus : {[{LRT=};{LED=550 Requested action not taken: mailbox unavailable};{FQDN=};{IP=}]}
TotalBytes : 3553
RecipientCount : 1
RelatedRecipientAddress :
Reference : {<8beab36d-836c-4ae5-8053-ada54b5dcc07@[MyServer]>}
MessageSubject : test6
Sender : [SenderEmail]
ReturnPath : [SenderEmail]
Directionality : Originating
TenantId :
OriginalClientIp :
MessageInfo : 2019-12-18T15:17:51.847Z;SRV=[MyServer]:TOTAL-SUB=0.749|SA=0.734|MTSSDA=0.002|M
TSSDC=0.002|MTSSDMO=0.015;MTSS|MTSSD;SRV=[MyServer]:TOTAL-HUB=1.812|SMRDI=0.003
|SMRCL=0.098|SMRC=0.098|SMR=0.101|CATSM-Malware Agent=0.018|CATSM=0.019|CATRS-Index Routing A
gent=0.004|CATRS=0.005|CCC=0.005|CATCM-McAfeeTxRoutingAgent=0.005|CATCM=0.005|CAT=0.038|QDE=0
.509|SMSC=1.009|SMS=0.158
MessageLatency :
MessageLatencyType : None
EventData : {[E2ELatency, 2.563], [ExternalSendLatency, 0.891],
[Microsoft.Exchange.Transport.MailRecipient.RequiredTlsAuthLevel, Opportunistic],
[Microsoft.Exchange.Transport.MailRecipient.EffectiveTlsAuthLevel, EncryptionOnly],
[DeliveryPriority, Normal], [AccountForest, [MyDomain]]}