HTTP Error 502.3 - Bad Gateway + Kotlin + Azure

Question

I am deploying a JAR built from Kotlin source with Spring Boot on an Azure app. instance. "It used to work". In an effort to track down the problem, I've modified it to serve a static page of HTML. When I browse to the page, the server logs this valid HTML document:

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IIS Detailed Error - 502.3 - Bad Gateway

HTTP Error 502.3 - Bad Gateway

There was a connection error while trying to route the request.

Most likely causes:

• The CGI application did not return a valid set of HTTP errors.
• A server acting as a proxy or gateway was unable to process the request due to an error in a parent gateway.

Things you can try:

• Use DebugDiag to troubleshoot the CGI application.
• Determine if a proxy or gateway is responsible for this error.

Detailed Error Information:

Module   httpPlatformHandlerNotification   ExecuteRequestHandlerHandler   httpPlatformHandlerMainError Code   0x8007042b Requested URL   https://AZUREAPPINSTANCE:80/Physical Path   D:\home\site\wwwrootLogon Method   AnonymousLogon User   Anonymous

More Information:

This error occurs when a CGI application does not return a valid set of HTTP headers, or when a proxy or gateway was unable to send the request to a parent gateway. You may need to get a network trace or contact the proxy server administrator, if it is not a CGI problem.

View more information »

Microsoft Knowledge Base Articles:

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and the browser shows The specified CGI application encountered an error and the server terminated the process.

Usually that means that the app. can't talk to some other service but here it is serving a static page of HTML. I think there is some network misconfiguration because if I go to https://ourapp/XYZ then the Requested URL is https://AZUREAPPINSTANCE:80/XYZ so something in the Azure network stack is rewriting the address (https on port 80!).

Answer 1

Here is the answer, even though I don't understand it.

Refer to the POM, posted in my earlier question.

If I remove the entire <pluginManagement> element, the deployed Azure app. works.