If you see the message:
The Google Account of a site owner has been disabled because of a perceived violation of the Terms of Service. The site owner needs to restore their Google Account before this site can be viewed. Learn more
Then, as the message suggests, one (or more) accounts that is an owner of the Site has been disabled.
If Google detects activity on a Google account which suggests that the account has been hacked or compromised in some way, they will disable Sites owned by that account until the verified owner restores access to the account. This is done to protect the Site(s) since if a Site Owner account has been compromised the Site(s) would be at risk. (It's possible the account was disabled temporarily and restored by Google before you even noticed it.)
You need to follow the instructions given by the link 'Learn More'. Once your account has been restored, it can take up to 24 hours for the site to be restored.
See also this page Forbidden 403 Error - Site disabled for a general discussion about Site disablements especially the section on Account disablements
If you have access to at least one account that is a Site owner then you can determine which other accounts are owners using Google's Webmaster tools. Make sure you are signed in with the owner account and go to: