Remove Server header on response on 500 HTTP Error - azure

Question

I have a REST API service deployed as an Azure App Service and i been trying to remove the Server header from response.
I tried adding a custom outgoing rule to Rewrite module.
In web.config i have
<rewrite>
<outboundRules>
<rule name="Change Server Header">
<match serverVariable="RESPONSE_Server" pattern=".+" />
<action type="Rewrite" value="My Server" />
</rule>
</outboundRules>
</rewrite>
I also applied a applicationHost.xdt transformation to applicationHost.config in order to add the RESPONSE_Server variable
<?xml version="1.0"?>
<configuration xmlns:xdt="http://schemas.microsoft.com/XML-Document-Transform">
<configSections>
<sectionGroup name="system.webServer" xdt:Locator="Match(name)">
<sectionGroup name="rewrite" xdt:Locator="Match(name)">
<section name="allowedServerVariables" overrideModeDefault="Allow" xdt:Locator="Match(name)" xdt:Transform="SetAttributes(overrideModeDefault)" />
</sectionGroup>
</sectionGroup>
</configSections>
<system.webServer>
<rewrite>
<allowedServerVariables>
<add name="RESPONSE_Server" xdt:Transform="InsertIfMissing" xdt:Locator="Match(name)" />
</allowedServerVariables>
</rewrite>
</system.webServer>
</configuration>
But i still see the Server response http header on a request like following which returns a 500 HTTP status code
https://api.internaltest.com/%3a/
The rewrite rule works in local IIS it removes the http header successfully... but not when doing it in Azure App Service.
Please tell me what i'm missing.
I mention that i have removeServerHeader="true" in web.config also but it only removes the server header on 404 bad request, not on 500 status code.
<security>
<requestFiltering removeServerHeader="true">
<requestLimits maxAllowedContentLength="2147483647" />
</requestFiltering>
</security>
Hope anyone can help me,
Thank you

Answer 1

I manged to make it work by adding the outbound rule in xdt file and not in web.config
Here is the correct application.Host.xdt hope it helps others... It replaces the server header with a value on 500 error HTTP response
<?xml version="1.0"?>
<configuration xmlns:xdt="http://schemas.microsoft.com/XML-Document-Transform">
<configSections>
<sectionGroup name="system.webServer" xdt:Locator="Match(name)">
<sectionGroup name="rewrite" xdt:Locator="Match(name)">
<section name="allowedServerVariables" overrideModeDefault="Allow" xdt:Locator="Match(name)" xdt:Transform="SetAttributes(overrideModeDefault)" />
</sectionGroup>
</sectionGroup>
</configSections>
<system.webServer>
<rewrite>
<allowedServerVariables>
<add name="RESPONSE_Server" xdt:Transform="InsertIfMissing" xdt:Locator="Match(name)" />
</allowedServerVariables>
<outboundRules xdt:Transform="InsertIfMissing">
<rule name="Change Server Header" xdt:Transform="InsertIfMissing" xdt:Locator="Match(name)">
<match serverVariable="RESPONSE_Server" pattern=".+" />
<action type="Rewrite" value="My Server" />
</rule>
</outboundRules>
</rewrite>
</system.webServer>
</configuration>