diff -u b/core/modules/config_translation/src/Tests/ConfigTranslationUiTest.php b/core/modules/config_translation/src/Tests/ConfigTranslationUiTest.php
--- b/core/modules/config_translation/src/Tests/ConfigTranslationUiTest.php
+++ b/core/modules/config_translation/src/Tests/ConfigTranslationUiTest.php
@@ -385,7 +385,7 @@
    * Tests the node type translation.
    */
   public function testNodeTypeTranslation() {
-    $type = $this->randomName();
+    $type = Unicode::strtolower($this->randomMachineName(16));
     $name = $this->randomString();
     $this->drupalLogin($this->admin_user);
     $this->drupalCreateContentType(array('type' => $type, 'name' => $name));
@@ -394,7 +394,7 @@
     $langcode = $this->langcodes[0];
     $translated_name = $langcode . '-' . $name;
     $edit = array(
-      "config_names[node.type.$type][name][translation]" => $translated_name,
+      "translation[config_names][node.type.$type][name]" => $translated_name,
     );
     $this->drupalPostForm("admin/structure/types/manage/$type/translate/$langcode/add", $edit, t('Save translation'));