diff --git a/extensions/microsoft-authentication/src/node/flows.ts b/extensions/microsoft-authentication/src/node/flows.ts
index 6ab5af4d04eb96..6aa49884123661 100644
--- a/extensions/microsoft-authentication/src/node/flows.ts
+++ b/extensions/microsoft-authentication/src/node/flows.ts
@@ -107,7 +107,8 @@ class UrlHandlerFlow implements IMsalFlow {
 			windowHandle,
 			claims,
 			resource,
-			redirectUri
+			redirectUri,
+			responseMode: 'form_post'
 		});
 	}
 }
diff --git a/extensions/microsoft-authentication/src/node/test/flows.test.ts b/extensions/microsoft-authentication/src/node/test/flows.test.ts
index 129fff04868d8b..4ef1b74528e110 100644
--- a/extensions/microsoft-authentication/src/node/test/flows.test.ts
+++ b/extensions/microsoft-authentication/src/node/test/flows.test.ts
@@ -214,6 +214,7 @@ suite('MSAL flow trigger', () => {
 		});
 
 		assert.strictEqual(cachedPca.interactiveRequests[0]?.resource, RESOURCE);
+		assert.strictEqual(cachedPca.interactiveRequests[0]?.responseMode, 'form_post');
 	});
 
 	test('device code flow forwards resource to acquireTokenByDeviceCode', async () => {