NServiceBus: Cannot enlist the transaction (failed to send msg to audit queue) - nservicebus

Question

I have an endpoint that works as a distributor with three other worker endpoints.
The handling endpoint of the received message opens a transaction and tries to import some xml data into an sql db. If some exception is thrown during this process, the exception is caught, the transaction is rolled back and the xml data is written to an error folder.
Simplified, it looks like that:
public void Handle(doSomethingCmd message)
{
System.Data.SqlClient.BeginTransaction();
try
{
//... some xml data import
throw new Exception();
//Commit if succeded
}
catch (Exception exception)
{
System.Data.IDbTransaction.Rollback();
//...Write file to error folder
}
}
In the first place, no retry happens after the transaction rollback. But when the message is sent again, all the worker endpoints (only the workers) get an exception (Cannot enlist transaction, failed to send msg to control queue --> see stacktrace below) and nservicebus does retry the message (this leads to the case, that the file appears several times in the error folder)
It looks like distributed transaction is in an invalid state. I could just handing over the exception (re-throw the exception), so nservicebus handles the rollback for me, but in that case the file is written to the error folder several times as well (due to retry mechanism)
Failed raising finished message processing event.|NServiceBus.Unicast.Queuing.FailedToSendMessageException: Failed to send message to address: someEndpoint.distributor.control#SRVPS01 ---> System.Messaging.MessageQueueException: Cannot enlist the transaction.
at System.Messaging.MessageQueue.SendInternal(Object obj, MessageQueueTransaction internalTransaction, MessageQueueTransactionType transactionType)
at System.Messaging.MessageQueue.Send(Object obj, MessageQueueTransactionType transactionType)
at NServiceBus.Transports.Msmq.MsmqMessageSender.Send(TransportMessage message, Address address) in c:\BuildAgent\work\31f8c64a6e8a2d7c\src\NServiceBus.Core\Transports\Msmq\MsmqMessageSender.cs:line 49
--- End of inner exception stack trace ---
at NServiceBus.Transports.Msmq.MsmqMessageSender.ThrowFailedToSendException(Address address, Exception ex) in c:\BuildAgent\work\31f8c64a6e8a2d7c\src\NServiceBus.Core\Transports\Msmq\MsmqMessageSender.cs:line 88
at NServiceBus.Transports.Msmq.MsmqMessageSender.Send(TransportMessage message, Address address) in c:\BuildAgent\work\31f8c64a6e8a2d7c\src\NServiceBus.Core\Transports\Msmq\MsmqMessageSender.cs:line 75
at NServiceBus.Distributor.MSMQ.ReadyMessages.ReadyMessageSender.SendReadyMessage(String sessionId, Int32 capacityAvailable, Boolean isStarting) in c:\BuildAgent\work\c3100604bbd3ca20\src\NServiceBus.Distributor.MSMQ\ReadyMessages\ReadyMessageSender.cs:line 62
at NServiceBus.Distributor.MSMQ.ReadyMessages.ReadyMessageSender.TransportOnFinishedMessageProcessing(Object sender, FinishedMessageProcessingEventArgs e) in c:\BuildAgent\work\c3100604bbd3ca20\src\NServiceBus.Distributor.MSMQ\ReadyMessages\ReadyMessageSender.cs:line 50
at System.EventHandler1.Invoke(Object sender, TEventArgs e)
at NServiceBus.Unicast.Transport.TransportReceiver.OnFinishedMessageProcessing(TransportMessage msg) in c:\BuildAgent\work\31f8c64a6e8a2d7c\src\NServiceBus.Core\Unicast\Transport\TransportReceiver.cs:line 435
NServicebus version: 4.6.0.0
Queueing: MSMQ

Answer 1

The worker ends it unit of work by sending a message back to the distributor. This send will join the existing distributed transaction. The error you get is caused by this new transactional resource trying to join an already failing transaction. Something has marked the distributed transaction as rolling back.
This is normally caused by your code. Either your database operation is failing somehow or you probably have exceeded the transaction timeout limit handling the message. (Default one minute)
Check your logs to see if you are using above the transaction timeout limit to process the message on the worker.