I am not Sure, check IW hosting webserver is up and running.
Check the logs -- there may be a problem with that .page file or with the site it is part of. (I believe that error message is the generic "something went wrong" error message.) For example if someone deleted the default.site file, or if you do not have permission to view the site file or page file, you might get that.What version of LiveSite are you using?