diff --git a/src/views/app.html b/src/views/app.html
index 02b0188e5..2a8fcf609 100644
--- a/src/views/app.html
+++ b/src/views/app.html
@@ -1236,10 +1236,11 @@
       <div class="card" ng-show="view === 'proxy'">
         <div class="row">
           <div class="col-md-12">
-            <form role="form" name="ProxyForm" ng-submit="proxy.submit()" autocomplete="off">
-              <div class="form-group">
+            <form role="form" name="proxyForm" ng-submit="proxy.submit()" autocomplete="off">
+              <div class="form-group" ng-class="{ 'has-error': !proxyForm.upstreamUri.$dirty && proxy.error }">
                 <label class="control-label" style="width: 100%">Upstream URI</label>
-                <input type="text" ng-model="proxy.upstreamUri" placeholder="" class="form-control"/>
+                <input type="text" ng-model="proxy.upstreamUri" name="upstreamUri" placeholder="" class="form-control"/>
+                <p class="text-danger" ng-show="!proxyForm.upstreamUri.$dirty && proxy.error">{{ proxy.error }}</p>
               </div>
 
               <input class="ng-hide" type="submit" ng-disabled="proxyForm.$invalid || proxy.busy"/>
diff --git a/src/views/app.js b/src/views/app.js
index 583963100..9b92549fb 100644
--- a/src/views/app.js
+++ b/src/views/app.js
@@ -1039,27 +1039,36 @@ angular.module('Application').controller('AppController', ['$scope', '$location'
 
     $scope.proxy = {
         busy: false,
-        error: {},
+        error: null,
         success: false,
 
         upstreamUri: '',
 
         show: function () {
-            $scope.proxy.error = {};
+            $scope.proxyForm.$setPristine();
+            $scope.proxy.error = null;
             $scope.proxy.upstreamUri = $scope.app.upstreamUri || '';
         },
 
         submit: function () {
             $scope.proxy.busy = true;
-            $scope.proxy.error = {};
+            $scope.proxy.error = null;
 
             var upstreamUri = $scope.proxy.upstreamUri.replace(/\/$/, '');
             Client.configureApp($scope.app.id, 'upstream_uri', { upstreamUri: upstreamUri }, function (error) {
+                $scope.proxy.busy = false;
+
+                if (error && error.statusCode === 400) {
+                    $scope.proxy.error = error.message;
+                    $scope.proxyForm.$setPristine();
+                    return;
+                }
                 if (error) return Client.error(error);
 
+                $scope.proxyForm.$setPristine();
+
                 $timeout(function () {
                     $scope.proxy.success = true;
-                    $scope.proxy.busy = false;
                 }, 1000);
             });
         }