diff --git a/lib/Routes/Config/ConfigAddEdit.php b/lib/Routes/Config/ConfigAddEdit.php
index 75f0db9a1..7a3aded32 100644
--- a/lib/Routes/Config/ConfigAddEdit.php
+++ b/lib/Routes/Config/ConfigAddEdit.php
@@ -29,16 +29,39 @@ public function __invoke(Request $request, Response $response, $args)
         $json = $this->getRequestData($request);
 
         $config_checked = false;
+        $dublicate_url = false;
+
         // check, if a config with the same data already exists:
+        $config = reset(Config::findBySql('service_url = ?', [$json['config']['service_url']]));
         if ($args['id']) {
-            $config = Config::find($args['id']);
-        } else {
-            $config = reset(Config::findBySql('service_url = ?', [$json['config']['service_url']]));
-
-            if (!$config) {
+            // PUT request - edit config
+            if ($config && $config->id !== (int)$args['id']) {
+                $dublicate_url = true;
+            }
+            else {
+                $config = Config::find($args['id']);
+            }
+        }
+        else {
+            // POST request - create config
+            if ($config) {
+                $dublicate_url = true;
+            } else {
                 $config = new Config;
             }
         }
+        // Throw error if the url is already used
+        if ($dublicate_url) {
+            return $this->createResponse([
+                'message'=> [
+                    'type' => 'error',
+                    'text' => sprintf(
+                        _('Eine Konfiguration mit der angegebenen URL ist bereits vorhanden: "%s"'),
+                        $json['config']['service_url']
+                    )
+                ],
+            ], $response);
+        }
 
         $new_settings = [];
         $stored_config = $config->toArray();
diff --git a/migrations/074_update_config_key.php b/migrations/074_update_config_key.php
new file mode 100644
index 000000000..befebb2c6
--- /dev/null
+++ b/migrations/074_update_config_key.php
@@ -0,0 +1,33 @@
+<?php
+
+class UpdateConfigKey extends Migration
+{
+    public function description()
+    {
+        return 'Add event state to videos, for enabling link to cutting tool and more';
+    }
+
+    public function up()
+    {
+        $db = DBManager::get();
+
+        $db->exec("ALTER TABLE `oc_config`
+            DROP INDEX service_url,
+            ADD UNIQUE KEY(service_url)
+        ");
+
+        SimpleOrMap::expireTableScheme();
+    }
+
+    public function down()
+    {
+        $db = DBManager::get();
+
+        $db->exec("ALTER TABLE `oc_config`
+            DROP INDEX service_url,
+            ADD UNIQUE KEY(service_url,service_user,service_password)
+        ");
+
+        SimpleOrMap::expireTableScheme();
+    }
+}
\ No newline at end of file