diff --git a/app/controllers/api/proxy.php b/app/controllers/api/proxy.php
index f9621fb05a..23916a114c 100644
--- a/app/controllers/api/proxy.php
+++ b/app/controllers/api/proxy.php
@@ -87,7 +87,11 @@ App::post('/v1/proxy/rules')
             $resourceInternalId = $function->getInternalId();
         }
 
-        $domain = new Domain($domain);
+        try {
+            $domain = new Domain($domain);
+        } catch (\Exception) {
+            throw new Exception(Exception::GENERAL_ARGUMENT_INVALID, 'Domain may not start with http:// or https://.');
+        }
 
         $ruleId = ID::unique();
         $rule = new Document([