How To: Remove browser security popups regarding SSL certificate revocation when accessing ArcGIS Online or ArcGIS Online resources
When accessing ArcGIS Online or resources from *.arcgis.com or *.arcgisonline.com, some users may be prompted in the browser with a popup with wording similar to the following:
"Revocation information for the security certificate for this site is note available. Do you want to proceed?"
By looking at the details of the SSL certificate, one can find the Certificate Revocation List URL. Adding the fully qualified domain name of that URL to the trusted sites in the browser or on a similar whitelist for forward proxies allows the CRL to be accessed by the browser, thus getting rid of the security prompt.
- Microsoft Community: How do I add a site to my "trusted sites" list?