Symptoms
Intermittently messages are not delivered and no non-delivery report (NDR) is generated in Microsoft Exchange Server 2019 or Exchange Server 2016. You eventually find that the missing messages are landed in the Poison message queue.
In addition, the following events are logged in the application log:
Time: DateTime
ID: 1051
Level: Warning
Source: MSExchange Extensibility
Machine:
Message: Agent 'Mailbox Rules Agent' caused an unhandled exception 'NotInBagPropertyErrorException: [0x66a5000b] SendReadNotifications' while handling event 'OnPromotedMessage'
Time: DateTime
ID: 25012
Level: Error
Source: MSExchangeTransportDelivery
Machine:
Message: An unhandled exception was thrown while processing data from client IP address <IPAddress>. SMTP state transitions: WaitingForGreeting -> GreetingReceived (EhloProcessed)
GreetingReceived -> WaitingForGreeting (XAnonymousTlsProcessed)
WaitingForGreeting -> GreetingReceived (EhloProcessed)
GreetingReceived -> GreetingReceived (XExpsProcessed)
GreetingReceived -> GreetingReceived (XSessionParamsProcessed)
GreetingReceived -> MailTransactionStarted (MailProcessed)
MailTransactionStarted -> WaitingForMoreRecipientsOrData (RcptProcessed)
WaitingForMoreRecipientsOrData -> ReceivingBdatChunks (BdatProcessed)
ReceivingBdatChunks -> ReceivingBdatChunks (BdatProcessed). Exception System.ExInvalidOperationException: Agent 'Mailbox Rules Agent' encountered an unexpected error while handling event 'OnPromotedMessage'. ---> Microsoft.Exchange.Data.Storage.NotInBagPropertyErrorException: [0x66a5000b] SendReadNotifications
Time: DateTime
ID: 10003
Level: Error
Source: MSExchangeTransportDelivery
Machine:
Message: The transport process failed during message processing with the following call stack: System.ExInvalidOperationException: Agent 'Mailbox Rules Agent' encountered an unexpected error while handling event 'OnPromotedMessage'. ---> Microsoft.Exchange.Data.Storage.NotInBagPropertyErrorException: [0x66a5000b] SendReadNotifications
Resolution
To fix this issue, install one of the following updates:
For Exchange Server 2019, install the Cumulative Update 7 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019.For Exchange Server 2016, install the Cumulative Update 18 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016.
References
Learn about the terminology that Microsoft uses to describe software updates.
