What to do if an error occurs during the extension installation using the key?

If you get this error ‘http://connect20.magentocommerce.com/community/Mss_Connector’ during the extension installation, then follow these steps:-

To resolve this problem just navigate to Settings and find Magento Connect Channel Protocol.
You have to change it from HTTP to FTP. This will resolve your problem.

If this method does not help you overcome the error, then let us know by emailing us at contact@magentomobileshop.com and we will help you out.