The reason for this issue is most likely due to the fact that after the upgrade your website has been moved to our paid servers. This means that the IP address of the server where your domain is hosted has been changed. Usually, it should take 1-12 hours for these changes to take effect. What we can recommend you to do is try cleaning your temporary internet files – cache, cookies, etc. For more information on how to do this, please check the next question from our FAQ.
If you have manually configured the DNS records for your domain you will have to update them again after the upgrade so they point to our paid servers.
If your website still does not respond please contact our technical support by opening a trouble ticket from the hosting control panel.
