I had similar message with another CMS. Try uninstalling it and installing it again. If X10 offer that LMS is because it can be installed on the servers, I suppose.
Too many plugins maybe?
Both sites are 503 server errors (server is currently unavailable (because it is overloaded or down for maintenance)
https://en.wikipedia.org/wiki/List_of_HTTP_status_codes
Can you list the plugins you are using?