Product:
Cognos Analytics 11.0.13
Microsoft Windows 2016 server

Problem:
Sometimes when user create a report they get a error similar to below, if you clear the users browser cache, you often get the error.

Error:
Message from webpage
Error: Startup Request Failed: The web request failed.:500
URL Rewrite Module Error
URL:../images/Corey_Active.png
at Anonymous function…

Solution:
Check the cognos folders, like C:\Program Files\ibm\cognos\analytics\webcontent\bi\samples\images\ for web.config files that is wrong.
Turn off IIS.
Remove the damage web.config file.
Start IIS.
Check that your BI folder rewrite rules for SSO is correct.
Check that WEBDAV is correct setup on your image folder.

More information:
https://www.ibm.com/support/pages/configuring-webdav-view-and-browse-images-ibm-cognos-analytics
https://www.ibm.com/support/pages/automate-configuration-microsofts-internet-information-service-support-ibm-cognos-analytics
https://info.motio.com/blog/setting-up-a-gateway-to-enable-sso-for-cognos-11
https://www.ibm.com/support/knowledgecenter/SSEP7J_11.1.0/com.ibm.swg.ba.cognos.inst_cr_winux.doc/c_enabling_single_signon_between_actdirsrv_and_cog_comp.html