Keycloak identity brokering (to Azure AD) blocked by corporate proxy on authorization_code exchange - proxy

Question

I have AzureAD as external OIDC provider registered at Keycloak. Keycloak redirects client authorization requests to AzureAD for providing the authorization. Keycloak is running on my workstation behind a corporate proxy, the corresponding Azure AD is hosted in the public internet. I'm able to connect to Azure AD with Postman from my local workstation.
The authorization via AzureAD works as expected (The user is prompted to put in her/his credentials and accept the consent). After successful authorization AzureAD responds with an authorization_code to the defined Keycloak return-url:
http://localhost:5000/auth/realms/lsp-api/broker/ms-azure-ad/endpoint?code=AQABAAIAAADX8GCi6Js6SK82TsD2Pb7rL__pDRDcKAqDqyTeTdzmbC9n3kcz5flc0q7zDRbK-WVLUpcUU65tWSh9C-opFiwtMZOACwGLQDgh4y4ScLW-dUGN7g3Ad3_aBqK-uHPgS3uKM1OlAIeSw3NSl1DMTKhH7SGQRGITP6ARIrCL9snqNRDUbHvhfKVlLMxmJTUk0bKDIT3PzM4nBSd1NwdXc9VZ9cCFnRMjlKfpRUx3guo-58tgSL5Vsaf8TvKg8B5TSYbiDzS49epFsU0Eg_PBs1JU4Q-8vOrN_wlV1zs1IUDYbUv8EdlMdqJkaT-nBTv-4Ab2Jf3X39u4m666kvcWmezGJ-NkjPqaOSK6eglWJfjW_z9-vHFQl6F9JxdCIlGbolyZyUpo0-a0LlnVVg2gyl1wJEOSnv5RvhmTZOqa1qWxZNsyG15JeQBkcK-J0XzWmn8CaeqzsJwFlNwkpzK_XaZW-KIsWayZ0Rz2HdDYh3Mre2I4uRmDyoQLiP60lYDaYowZZ11jSBy_87vFL2alK-5sGyUajs6kODfsoSlEGHhWJeHMiC2-jYm0gMNTQIvUMYpLJRpgKX6v3n-E3Q7ZlYD_VAWOnDZBCR5iaTsUOxuXN6CiC4p01N47c4QG4Y8A9lTbVXDvVcxSBz8H7uM5DfawFGUKpSCobI9V1XKnyw1R8UXTObqmEq8gA4jBzaRZb89qAnlZ6X-w39LbLWE7MUlL0Ok8LP-7omQlVei6AdEMfrIaHNIBUFimHLgKjiqcG2ogAA&state=FevrPXHHXkICQjFEYJ_3ZyvfZ2Y9E6iM5foCcOvk5C8.jXAAgdz4mnA.lsp-api&session_state=8cb0539a-b775-4de6-b334-5cb24caeb685
This response is sent with the status code 502, Bad Gateway. Furthermore the error-msg "Unexpected error when authenticating with Identity Provider" is displayed.
I already tried to send the returned authorization_code manually to the AzureAD /token endpoint and I received the access_token and the id_token back. So the problem seems to be the response-handling on the Keycloak-side.
Expected behavior would have been:
AzureAD responds to Keycloak with the authorization_code
Keycloak is able to exchange the authorization_code for an access_token (mb. in addition an id_token)
What does not work:
Keycloak is not able to exchange the authorization_code for an access_token, but throws the "Unexpected error when authenticating with Identity Provider" error-message.
Keycloak setup:
Keycloak Version: 4.1.0.Final
The AzureAD Reply-URL is set to http://localhost:5000/auth/realms/lsp-api/broker/ms-azure-ad/endpoint .
Edit
I did some more research and found out that this is probably a corporate proxy issue. The proxy is situated between Keycloak (running on my machines localhost) and AzureAD. So how do I set the proxy for Keycloaks Identity Brokering? The relevant Keycloak logs:
org.keycloak.broker.oidc.AbstractOAuth2IdentityProvider] (default task-122) Failed to make identity provider oauth callback: org.apache.http.conn.HttpHostConnectException: Connect to login.microsoftonline.com:443 [login.microsoftonline.com/40.112.64.25, login.microsoftonline.com/104.41.216.18, login.microsoftonline.com/104.41.216.16] failed: Connection refused: connect
at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:158)
at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:353)
at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:380)
at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:236)
at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:184)
at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:88)
at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:184)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:82)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:107)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:55)
at org.keycloak.broker.provider.util.SimpleHttp.makeRequest(SimpleHttp.java:185)
at org.keycloak.broker.provider.util.SimpleHttp.asResponse(SimpleHttp.java:154)
at org.keycloak.broker.provider.util.SimpleHttp.asString(SimpleHttp.java:146)
at org.keycloak.broker.oidc.AbstractOAuth2IdentityProvider$Endpoint.authResponse(AbstractOAuth2IdentityProvider.java:405)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.jboss.resteasy.core.MethodInjectorImpl.invoke(MethodInjectorImpl.java:140)
at org.jboss.resteasy.core.ResourceMethodInvoker.invokeOnTarget(ResourceMethodInvoker.java:295)
at org.jboss.resteasy.core.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:249)
at org.jboss.resteasy.core.ResourceLocatorInvoker.invokeOnTargetObject(ResourceLocatorInvoker.java:138)
at org.jboss.resteasy.core.ResourceLocatorInvoker.invoke(ResourceLocatorInvoker.java:107)
at org.jboss.resteasy.core.ResourceLocatorInvoker.invokeOnTargetObject(ResourceLocatorInvoker.java:133)
at org.jboss.resteasy.core.ResourceLocatorInvoker.invoke(ResourceLocatorInvoker.java:101)
at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:406)
at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:213)
at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:228)
at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:56)
at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:51)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129)
at org.keycloak.services.filters.KeycloakSessionServletFilter.doFilter(KeycloakSessionServletFilter.java:90)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84)
at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at org.wildfly.extension.undertow.deployment.GlobalRequestControllerHandler.handleRequest(GlobalRequestControllerHandler.java:68)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:292)
at io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:81)
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:138)
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:135)
at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48)
at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
at org.wildfly.extension.undertow.security.SecurityContextThreadSetupAction.lambda$create$0(SecurityContextThreadSetupAction.java:105)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1508)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1508)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1508)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1508)
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:272)
at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:104)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:326)
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:812)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.TwoStacksPlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at org.apache.http.conn.ssl.SSLConnectionSocketFactory.connectSocket(SSLConnectionSocketFactory.java:337)
at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:141)
... 74 more

Answer 1

This exception means that there is no service listening on the IP/port you are trying to connect to:
You are trying to connect to the wrong IP/port.
You have not started your server.
Your server is not listening for connections.
On Windows servers, the listen backlog queue is full.
You can try to replace the localhost with your IP address. Also do ensure there's no firewall blocking the connection.

Answer 2

You should be able to set proxy for JVM like
-Dhttp.proxyHost=proxy.example.com -Dhttp.proxyPort=3128