Jira Service Desk Reverse Proxy Issue IIS

[IT]

We have our Jira service desk installed on the same server as our IIS server. Not wanting our users to have to worry about remembering port 8080, we setup a reverse proxy on IIS for servicedesk.domain.com. The URL Rewrite rule pattern is (.*) and it rewrites to http://servicedesk.domain.com:8080/{R:1}. 

In our server.xml we have: 

 <Connector port="8080" maxThreads="150" minSpareThreads="25" connectionTimeout="20000" enableLookups="false"
 maxHttpHeaderSize="8192" protocol="HTTP/1.1" useBodyEncodingForURI="true" redirectPort="8443" 
 acceptCount="100" disableUploadTimeout="true" proxyName="servicedesk.domain.com" proxyPort="80"
 scheme="http"/>

The reverse proxy is working fine for many things, but it isn't working for the "Dashboards", "Projects", and "Issues" dropdowns on top. I tried Firefox, Chrome and IE. When I dug into it further I can see that clicking to get those dropdowns is calling out to http://servicedesk.domain.com/rest/api/1.0/menus/browse_link?inAdminMode=false&_=1532395899993 and the server is responding with a 404, not found error. If I paste that link directly into a browser without the port I get a 404 error, but if add the port 8080, I get the XML document as a response. 

In the IIS log I see this. 10.1.1.20 is the IIS server and 10.2.4.42 is my client.

2018-07-24 02:21:09 10.1.1.20 GET /rest/api/1.0/menus/browse_link inAdminMode=false&_=1532395899993&X-ARR-CACHE-HIT=0&X-ARR-LOG-ID=b8d88073-9037-4234-9a96-fcac9d9d8763&SERVER-STATUS=404 80 - 10.2.4.42 Mozilla/5.0+(Windows+NT+10.0;+Win64;+x64)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Chrome/67.0.3396.99+Safari/537.36 - 404 0 0 15

Has anyone seen anything like this? I have been staring at it a few hours now and am starting to go cross-eyed.  Any help or suggestions would be much appreciated.

[Boris Berenberg - Atlas Authority]

Did you go through https://confluence.atlassian.com/kb/proxying-atlassian-server-applications-with-microsoft-internet-information-services-iis-833931378.html#ProxyingAtlassianserverapplicationswithMicrosoftInternetInformationServices(IIS)-PartB.ConfigureInternetInformationServices(IIS) step by step? I am guessing you overlooked one of them.

[IT]

I did actually. Those were the steps I followed to set it up.  The only thing I didn't do is "#2 - Set the context path." because it says its only needed if you want to access the service desk via the context path. Could that be it?

Does the physical path to the IIS Website folder matter? I have it pointed to C:\inetpub\wwwroot\JiraServiceDesk which only has the web.config in it with the rewrite rule. 

[Boris Berenberg - Atlas Authority]

I would look in the Jira access logs to understand what request is happening there. The ARR cache params in the URL may be breaking something.