diff --git a/src/js/client.js b/src/js/client.js
index 2fd491e04..5f9e5fa0f 100644
--- a/src/js/client.js
+++ b/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);
diff --git a/src/views/apps.js b/src/views/apps.js
index aac6ce28e..f7623b49d 100644
--- a/src/views/apps.js
+++ b/src/views/apps.js
@@ -136,6 +136,10 @@ angular.module('Application').controller('AppsController', ['$scope', '$location
                 if (error) {
                     if (error.statusCode === 409 && (error.message.indexOf('is reserved') !== -1 || error.message.indexOf('is already in use') !== -1)) {
                         $scope.appConfigure.error.port = error.message;
+                    } else if (error.statusCode === 409 && error.message.indexOf('mailbox') !== -1 ) {
+                        $scope.appConfigure.error.mailboxName = error.message;
+                        $scope.appConfigureForm.mailboxName.$setPristine();
+                        $('#appConfigureMailboxNameInput').focus();
                     } else if (error.statusCode === 409) {
                         $scope.appConfigure.error.location = 'This name is already taken.';
                         $scope.appConfigureForm.location.$setPristine();
@@ -150,10 +154,6 @@ angular.module('Application').controller('AppsController', ['$scope', '$location
                         $scope.appConfigure.error.xFrameOptions = error.message;
                         $scope.appConfigureForm.xFrameOptions.$setPristine();
                         $('#appConfigureXFrameOptionsInput').focus();
-                    } else if (error.statusCode === 400 && error.message.indexOf('mailbox') !== -1 ) {
-                        $scope.appConfigure.error.mailboxName = error.message;
-                        $scope.appConfigureForm.mailboxName.$setPristine();
-                        $('#appConfigureMailboxNameInput').focus();
                     } else {
                         $scope.appConfigure.error.other = error.message;
                     }