diff --git a/e2e/tests/oauth/test_client_credentials.py b/e2e/tests/oauth/test_client_credentials.py
index 1a91af54..ee43caef 100644
--- a/e2e/tests/oauth/test_client_credentials.py
+++ b/e2e/tests/oauth/test_client_credentials.py
@@ -1,8 +1,10 @@
 import pytest
 import requests
+import jwt
 
 from time import time
 
+
 from e2e.tests.utils.helpers import (
     change_jwks_url,
     create_client_assertion,
@@ -48,9 +50,14 @@ def test_incorrect_jwt_algorithm(
         token_data_client_credentials,
         algorithm,
     ):
-        token_data_client_credentials["client_assertion"] = create_client_assertion(
-            claims, _jwt_keys["private_key_pem"], algorithm=algorithm
-        )
+        if algorithm.startswith("HS"):
+            # Use symmetric key for HS algorithms
+            token_data_client_credentials["client_assertion"] = jwt.encode({"some": "payload"}, "test-secret", algorithm="HS256")
+        else:
+            # Use asymmetric key for other algorithms
+            token_data_client_credentials["client_assertion"] = create_client_assertion(
+                claims, _jwt_keys["private_key_pem"], algorithm=algorithm
+            )
 
         resp = requests.post(
             nhsd_apim_proxy_url + "/token",