The “Service Unavailable” message is just due to the sheer amount of Cloud WordPress users who are active at the same time. We have over 75,000 active websites signed on and using the service. The error message normally only last about 3 – 5 minutes on average. You can try clearing your cache and reloading the page or try accessing the URL in a different web browser.
Keep in mind “Cloud WordPress” is for site staging and development purposes only and should not be used in place of a traditional web host.
I hope this helps. Please reach back out if you need further assistance.
Also having this issue for over 12 hours. I paid for the premium and cannot login to create a new instance to test. Using the Google social login method. Tried manual login but it is forcing me to use the social. Tried 3 other browsers, all have the same result.