How to fix issue with subscribing to a message in my .net application from a topic

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How to fix issue with subscribing to a message in my .net application from a topic

Boddu, Yashwanth 0

Facing issue with processing message from servicebus topic in .net application.
The subscribing service is part of applicaiton which has reference to project where Messagehandler is implemented. Service bus message is reaching the subscription but my service is not getting the message.
Below attaching references.
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Jack Dang (WICLOUD CORPORATION) 17,425 Microsoft External Staff Moderator

Hi @Boddu, Yashwanth ,

Thanks for reaching out.

It looks like the main issue is that your OutboundCommunicationEventHub class is trying to implement the same generic interface IAsbMessageProcessor twice with different types (EmailRequestMessage and SMSRequestMessage). In C#, this isn’t allowed because both implementations define a ProcessMessage method with the same name, which causes a conflict. That’s why your service never gets the messages.

To resolve this, you have a few options:

Create one class to handle emails and another for SMS. Each class implements IAsbMessageProcessor<T> for its specific type. This is the simplest approach and keeps things clear.
Define a common interface without the generic parameter, then have each message type implement it. Your handler can then work with the base interface and delegate to the correct processor internally.
Keep one central class that receives all messages but routes them to the appropriate processor based on the message type.

Option 1 is usually the quickest to get working, while options 2 or 3 give more flexibility if you plan to handle more message types in the future.

Hope this helps! If my answer was helpful - kindly follow the instructions here so others with the same problem can benefit as well.

Boddu, Yashwanth 0 Reputation points

2026-02-03T08:03:15.3766667+00:00

Tried this but no luck.
I have removed the inheritance of IAsbMessageProcessor with typeEmailRequestMessage keeping only 1 still didn't wokr
Jack Dang (WICLOUD CORPORATION) 17,425 Reputation points Microsoft External Staff Moderator

2026-02-04T08:08:13.84+00:00
Hi @Boddu, Yashwanth ,

If using a single IAsbMessageProcessor<T> didn’t fix the issue, here are a few common things to check:

First, make sure your processor is actually registered in DI and that the hosted service can resolve it. Sometimes it just isn’t being picked up.

Double-check that your ServiceBusProcessor is pointing to the right subscription and that you’re calling StartProcessingAsync(). Don’t forget to attach both ProcessMessageAsync and ProcessErrorAsync.

Look at your subscription rules or filters. If you’re using things like CorrelationId or Subject, make sure they match the messages you’re sending. You can try a simple default rule with no filters just to confirm messages are flowing.

Check the dead-letter and active message counts. If CompleteMessageAsync isn’t called correctly, or if deserialization fails, messages can disappear quietly.

Make sure your message deserialization matches EmailRequestMessage exactly - property names, casing, and content-type all need to line up. Logging the raw body and properties can help a lot here.

Take a look at concurrency and auto-complete settings. If you’re manually completing messages, make sure AutoCompleteMessages is turned off.

Finally, put a simple log inside your handler to confirm it’s actually being invoked. If you don’t see it, the problem is happening before the handler even gets the message.

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How to fix issue with subscribing to a message in my .net application from a topic

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