Fix error handling

src/js/client.js

@@ -377,6 +377,8 @@ angular.module('Application').service('Client', ['$http', '$interval', 'md5', 'N
             enableBackup: config.enableBackup
         };
 
+        if ('mailboxName' in config) data.mailboxName = config.mailboxName;
+
         post('/api/v1/apps/' + id + '/configure', data).success(function (data, status) {
             if (status !== 202) return callback(new ClientError(status, data));
             callback(null);