In order to fix the issue, navigate to Start > Control Panel > System and Security > Windows Firewall, press the Turn Windows Firewall on or off button and check the both Turn off Windows Firewall (not recommended) boxes:
Also, temporarily disable your antivirus program. If the problem persists, from the Internet Explorer Tools menu select Internet Options and click the Security tab. Press the Trusted sites icon and then Sites. Type the Optonline URL in the provided field and click Add.