diff -u b/tests/src/Functional/IntegrationTest.php b/tests/src/Functional/IntegrationTest.php
--- b/tests/src/Functional/IntegrationTest.php
+++ b/tests/src/Functional/IntegrationTest.php
@@ -411,7 +411,7 @@
     $this->assertEquals(1, count($elements), 'Machine name cannot be changed.');
 
     // Test the AJAX functionality for configuring the tracker.
-    $edit = ['tracker' => $this->serverBackend];
+    $edit = ['tracker' => 'search_api_test'];
     $this->submitForm($edit, 'tracker_configure');
     $edit['tracker_config[foo]'] = 'foobar';
     $this->submitForm($edit, $this->t('Save'));