diff --git a/litellm/proxy/proxy_server.py b/litellm/proxy/proxy_server.py
index 079b5294472..5a1b3c6e72a 100644
--- a/litellm/proxy/proxy_server.py
+++ b/litellm/proxy/proxy_server.py
@@ -1766,7 +1766,9 @@ class ProxyConfig:
             )
             if master_key and master_key.startswith("os.environ/"):
                 master_key = litellm.get_secret(master_key)
-            litellm_master_key_hash = ph.hash(master_key)
+
+            if master_key is not None and isinstance(master_key, str):
+                litellm_master_key_hash = ph.hash(master_key)
             ### CUSTOM API KEY AUTH ###
             ## pass filepath
             custom_auth = general_settings.get("custom_auth", None)
diff --git a/litellm/tests/test_proxy_custom_auth.py b/litellm/tests/test_proxy_custom_auth.py
index 55ab456245a..d4c39e3d5d6 100644
--- a/litellm/tests/test_proxy_custom_auth.py
+++ b/litellm/tests/test_proxy_custom_auth.py
@@ -55,7 +55,7 @@ def test_custom_auth(client):
         }
         # Your bearer token
         token = os.getenv("PROXY_MASTER_KEY")
-
+        print(f"token: {token}")
         headers = {"Authorization": f"Bearer {token}"}
         response = client.post("/chat/completions", json=test_data, headers=headers)
         pytest.fail("LiteLLM Proxy test failed. This request should have been rejected")