When submitting a body > 30mb (default) locally, my application correctly throws 413. However, once it reaches Azure web app (containerized) it throws a 500 instead. This seems to be caused by the IIS proxy inbetween us and container. We have tried to change the MaxBodySize in web.config inside our container/app which had no effect. There is also no web.config in /home/wwwroot/ folder to edit and no way to create one any more via advanced tools.
The issue is not the 413 error as I have setup an endpoint that just returns a 413 error code and that works fine. Only when there is a large body does this error occur.
How can I either disable the IIS proxy grabbing this error and throwing a new 500 in its place. Or set the maxAllowedContentLength on the IIS proxy to be larger then the applications so the 413 comes through?
As Lex Li states in their comment, Linux container apps use YARP not IIS as a proxy so there would never be a way to achieve this.