Summary:

During our session we confirmed all the IIS settings were as expected including rights on Sage CRM folder structure.

We then noticed all the URL are been redirected to FQDN even when using internal requests like http://localhost. This gave us indication of redirection may not be working properly. 



Symptoms: 

1. Issue when exporting to excel:

"Task with given trackingId does not exist&"

2. Unable to edit MailChimp Configuration Screen



Resolution: 

Changed system behaviour to use “Custom server name for internal reqs:” to FQDN instead of http://localhost followed by refreshing custom parameters meta-data and restarting tomcat fixed this issue.

More Information:

After making these changes issue with MailChimp setup and export to excel are resolved