diff --git a/fetch/local-network-access/redirect.https.window.js b/fetch/local-network-access/redirect.https.window.js
index f8a53ad1889e617..edbd5a19fbc963c 100644
--- a/fetch/local-network-access/redirect.https.window.js
+++ b/fetch/local-network-access/redirect.https.window.js
@@ -365,8 +365,8 @@ promise_test(t => fetchTest(t, {
     server: Server.HTTPS_LOCAL,
     treatAsPublic: true,
   },
-  server: Server.HTTPS_PRIVATE,
   target: {
+    server: Server.HTTPS_PRIVATE,
     behavior: {
       preflight: PreflightBehavior.noPnaHeader(token()),
       response: ResponseBehavior.allowCrossOrigin(),
diff --git a/fetch/local-network-access/resources/support.sub.js b/fetch/local-network-access/resources/support.sub.js
index c07fd2c2acee689..0cf3d2532e7ffd5 100644
--- a/fetch/local-network-access/resources/support.sub.js
+++ b/fetch/local-network-access/resources/support.sub.js
@@ -205,6 +205,7 @@ function sourceResolveOptions({ server, treatAsPublic }) {
 //   - `response`: The result of calling one of `ResponseBehavior`'s methods.
 //   - `redirect`: A URL to which the target should redirect GET requests.
 function preflightUrl({ server, behavior }) {
+  assert_not_equals(server, undefined, 'server');
   const options = {...server};
   if (behavior) {
     const { preflight, response, redirect } = behavior;