I recently encountered the following problem and google only returned a single hit so I thought I’d share…
Having deployed my AIF (AX2012) service to my IIS instance I tried browsing it and received the error 503 – service unavailable.
The event log stated the following error:
“Message: Could not load type ‘Microsoft.Dynamics.Ax.Services.Host.AxServiceAutoStartProvider’ from assembly ‘Microsoft.Dynamics.IntegrationFramework.WebService.Process’.”
In the IIS manager I could see that the application pool was stopped and could not be started. After having verified the credentials of the identity the problem was still there.
I verified that all assemblies were to be found in the bin folder of the website – I found this to be ok.
I switched the managed pipeline of the application pool to classic:
Now I was able to browse the service, but received an authentication error instead stating that I didn’t have the proper privileges to browse the service.
I checked the Authentication feature of the website and found that “windows authentication” was missing.
I installed the feature from the server manager (remember to restart IIS and the IIS manager) and voila – problem solved.
I hope You will find this usefull, should you end up facing the same problem.