AX 2012 R3 - AIF service fails (“Duplicate type with name ‘Dynamics.Ax.Application.*’” error)

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Posted on by HY-12030737-0

Hi everyone,

I’m currently facing a critical issue after deploying a working AIF web service from our test environment to production in Dynamics AX 2012 R3. I would greatly appreciate any guidance or suggestions from the community.

Background

In our test environment, I created a custom AIF service, configured the service group, and successfully tested it. All operations, including SOAP requests and responses, worked as expected.

After validating the service in the test environment, I moved the exact same AIF service objects to the live (production) environment. This includes:

Service class and data contracts
Service node
Service group deployment

Problem

Once deployed in production, the service fails to start. Every time I try to access the service URL, the IIS Application Pool for MicrosoftDynamicsAXAif60 automatically goes into a “Stopped” state.

Event Viewer logs provide the following error:

I also noticed similar duplicate type errors referencing other custom classes prefixed with XXX_ in the same assembly.

Steps I’ve Tried

So far, I have attempted the following standard solutions to fix the problem:

Stopped IIS and AOS services on the production server.
Deleted the relevant records from the SYSXPPASSEMBLY table in SQL for the affected objects.
Performed full CIL compilation (both incremental and full compilation) to refresh the assemblies.
Redeployed the service group through AOT.
Restarted AOS and IIS to apply all changes.

Despite these steps, the issue persists. The IIS Application Pool still stops immediately, and the duplicate type error continues to appear.

Additional Information

The same service works perfectly in the test environment with the exact same configuration and code.
I have checked the AOT for duplicate class names and there are no manually duplicated classes.
The production environment is running Dynamics AX 2012 R3 (6.3.6000.149) with .NET Framework 4.8.
The AOS and IIS are on the same server.

Questions

Has anyone encountered this duplicate type error when moving a service from test to production?
Could there be hidden assembly or IL conflicts causing IIS to crash?
Are there any additional steps I should take to completely remove the duplicate type and get the AIF service running in production?
Could this be related to XppIL cache, model conflicts, or leftover test environment artifacts?

Any help, hints, or detailed instructions on how to resolve this would be greatly appreciated 🙏

Categories:

Microsoft Dynamics AX

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André Arnaud de Cal... 305,465 Super User 2026 Season 1 on at

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Hi,

I haven't encountered this issue myself before. AX2012 is a long time ago for me. Do you have the Test and Production instances running on the same physical server?

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Martin Dráb 239,660 Most Valuable Professional on at

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How did you move the code? You talked about individual objects, but the correct way of deploying code is either deploying models or the whole modelstore. If you moved individual elements, your process is wrong.

Also, you mentioned generating CIL but not compiling X++. That's wrong too; CIL generation depends on information from X++ compiler. Note that compilation and CIL generation in PROD isn't needed if you deploy the whole modelstore, which also reduces downtime of your production environment.

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Sohaib Cheema 49,668 Super User 2026 Season 1 on at

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Duplicate assembly was a common error in AX2012.

Some of those situations needed truncating a table from SQL that has assembly/compile information and redoing compile and generating CIL.

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HY-12030737-0 86 on at

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When I was creating an advanced inbound web service in the test environment, the service link section showed a link with the extension of the live environment. I selected that link and was fetching and saving data in the test environment.

However, to avoid using the same WSDL, I created a service and service group from scratch in the live environment.
I wanted to test the service in the live environment, but it kept crashing to the MicrosoftDynamicsAXAif60 stopped error in IIS, and I couldn't test my service in the live environment. I tried everything I saw in the Dynamics blogs; I fully compiled X++, deleted the SYSXPPASSEMBLY table in SQL, generated a full CIL, downgraded and then rolled back the version.

Despite this, I've been getting the same error for four days.

When I type the service WDSL into the browser, I get a 503 error.

Furthermore, my services running in the test environment have stopped working (most likely due to an IIS error). What I don't understand is why this service, which worked flawlessly in the test environment, doesn't work in the live environment, disrupting the operation of other services in the test environments.

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