diff --git a/core/modules/rest/src/Routing/ResourceRoutes.php b/core/modules/rest/src/Routing/ResourceRoutes.php
index db439dc..c711bbe 100644
--- a/core/modules/rest/src/Routing/ResourceRoutes.php
+++ b/core/modules/rest/src/Routing/ResourceRoutes.php
@@ -71,6 +71,10 @@ protected function alterRoutes(RouteCollection $collection) {
 
     // Iterate over all enabled resource plugins.
     foreach ($enabled_resources as $id => $enabled_methods) {
+      // rest.settings.yml includes non-existing plugins at the moment.
+      if (!$this->manager->hasDefinition($id)) {
+        continue;
+      }
       $plugin = $this->manager->getInstance(array('id' => $id));
 
       foreach ($plugin->routes() as $name => $route) {