Intercom Reverse IIS Proxy for Let's Encrypt SSL

web.config

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <system.webServer>
		<staticContent>
			  <clientCache cacheControlMode="UseMaxAge" cacheControlMaxAge="1.00:00:00" />
		</staticContent>		
        <rewrite>
            <rules>
				<!-- Make all requests https -->
                <rule name="Https redirect" stopProcessing="true">
                    <match url="(.*)" />
                    <action type="Redirect" url="https://{HTTP_HOST}/{R:1}" redirectType="Permanent" />
                    <conditions>
                        <add input="{HTTP_HOST}" pattern="^support.yourdomain.com$" />
                        <add input="{HTTPS}" pattern="^OFF$" />
                    </conditions>
                </rule>			
				
				<!-- Allow let's encrypt to generate a cert for this site -->
                <rule name="LetsEncrypt" stopProcessing="true">
                    <match url=".well-known/acme-challenge/*" />
                    <conditions logicalGrouping="MatchAll" trackAllCaptures="false" />
                    <action type="None" />
                </rule>
            
				<!-- Reverse proxy -->
                <rule name="ReverseProxyInboundRule1" stopProcessing="true">
                    <match url="(.*)" />
                    <conditions logicalGrouping="MatchAll" trackAllCaptures="false">
                        <add input="{HTTP_HOST}" pattern="^support.yourdomain.com$" />
                    </conditions>
                    <action type="Rewrite" url="https://custom.intercom.help:443/{R:1}" />
					<serverVariables>
						<set name="HTTP_X_FORWARDED_HOST" value="support.yourdomain.com" />
					</serverVariables>
                </rule>
			</rules>
        </rewrite>
        <httpProtocol>
            <customHeaders>
                <remove name="X-Powered-By" />
                <add name="strict-transport-security" value="max-age=16070400" />
            </customHeaders>
        </httpProtocol>
    </system.webServer>
</configuration>