If you happened to reset your Sync Password there won't be any data on the Sync server. The reset clears all your data from the server to allow you to get a fresh start with that Firefox Account. And since your data was encrypted from the password, that data would be useless to you with a different password - the data couldn't be decrypted.

You can check the about:sync-log page via the location/address bar to see if there are recent error logs available. You can temporarily set the services.sync.log.appender.file.logOnSuccess pref to true on the about:config page to also get a log of a successful Sync. Do not forget to reset the services.sync.log.appender.file.logOnSuccess pref to false after you have finished testing Sync or you will end up with a lot of unnecessary log files once the issue is resolved. You can upload a recent log if the log is too big to put in a reply.

• http://pastebin.mozilla.org

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

• http://kb.mozillazine.org/about:config