Find out What does mean "Error connecting to the server: 542"

If you are getting an error with the code 542 while updating the extension from your admin panel - it means that your license key is already registered with another domain (website).

Personal license gives you right to use the extension only on one website (domain). To use it on another website you need to make purchase another purchase of regular license or you can purchase an extended license and use the extension on unlimited number of websites/domains.