Why am I getting "Access Denied"?
If your screenshot shows an "Access Denied" page, this indicated that the target site has a WAF (web application firewall) blocking crawlers. The solution is to Whitelist Stillio IP addresses which requires administrative control of that site.
A workaround can be to select a different country in the URL Settings > Location list. This will use different IP addresses than the main pool of IP's from the Amazon AWS Data Center that runs our screenshot engine.