diff --git a/litellm/proxy/auth/auth_exception_handler.py b/litellm/proxy/auth/auth_exception_handler.py
index 9c306acd2c6..b34cd1d12b4 100644
--- a/litellm/proxy/auth/auth_exception_handler.py
+++ b/litellm/proxy/auth/auth_exception_handler.py
@@ -76,11 +76,17 @@ class UserAPIKeyAuthExceptionHandler:
                 use_x_forwarded_for=general_settings.get("use_x_forwarded_for", False),
             )
             verbose_proxy_logger.exception(
-                "litellm.proxy.proxy_server.user_api_key_auth(): Exception occured - {}\nRequester IP Address:{}".format(
-                    str(e),
+                "litellm.proxy.proxy_server.user_api_key_auth(): Exception occured - {}\nRequester IP Address:{}\nRoute: {}\nModel: {}".format(
+                    getattr(e, "message", str(e)),
                     requester_ip,
+                    route,
+                    request_data.get("model", "unknown"),
                 ),
-                extra={"requester_ip": requester_ip},
+                extra={
+                    "requester_ip": requester_ip,
+                    "route": route,
+                    "model": request_data.get("model"),
+                },
             )
 
             # Log this exception to OTEL, Datadog etc
@@ -110,7 +116,7 @@ class UserAPIKeyAuthExceptionHandler:
                 )
             if isinstance(e, HTTPException):
                 raise ProxyException(
-                    message=getattr(e, "detail", f"Authentication Error({str(e)})"),
+                    message=getattr(e, "detail", f"Authentication Error({getattr(e, 'message', str(e))})"),
                     type=ProxyErrorTypes.auth_error,
                     param=getattr(e, "param", "None"),
                     code=getattr(e, "status_code", status.HTTP_401_UNAUTHORIZED),
@@ -118,7 +124,7 @@ class UserAPIKeyAuthExceptionHandler:
             elif isinstance(e, ProxyException):
                 raise e
             raise ProxyException(
-                message="Authentication Error, " + str(e),
+                message="Authentication Error, " + getattr(e, "message", str(e)),
                 type=ProxyErrorTypes.auth_error,
                 param=getattr(e, "param", "None"),
                 code=status.HTTP_401_UNAUTHORIZED,
diff --git a/tests/test_litellm/proxy/auth/test_auth_exception_handler.py b/tests/test_litellm/proxy/auth/test_auth_exception_handler.py
index 3e780c6ee92..78956837ef3 100644
--- a/tests/test_litellm/proxy/auth/test_auth_exception_handler.py
+++ b/tests/test_litellm/proxy/auth/test_auth_exception_handler.py
@@ -112,6 +112,61 @@ async def test_handle_authentication_error_budget_exceeded():
     assert exc_info.value.type == ProxyErrorTypes.budget_exceeded
 
 
+@pytest.mark.asyncio
+async def test_proxy_exception_message_logged_correctly():
+    """
+    Regression test for #25361 — ProxyException.message must appear in the log,
+    not an empty string from str(ProxyException(...)).
+    """
+    handler = UserAPIKeyAuthExceptionHandler()
+
+    proxy_exc = ProxyException(
+        message="Model not allowed for this key",
+        type=ProxyErrorTypes.auth_error,
+        param=None,
+        code=401,
+    )
+
+    # Confirm the root cause: str() on ProxyException is empty
+    assert str(proxy_exc) == ""
+    # And that .message holds the real text
+    assert proxy_exc.message == "Model not allowed for this key"
+
+    mock_request = MagicMock()
+    mock_request_data = {"model": "gpt-4o"}
+    mock_route = "/v1/chat/completions"
+    mock_span = None
+    mock_api_key = "sk-test"
+
+    with patch(
+        "litellm.proxy.proxy_server.general_settings",
+        {"allow_requests_on_db_unavailable": False},
+    ), patch(
+        "litellm.proxy.proxy_server.proxy_logging_obj.post_call_failure_hook",
+        new_callable=AsyncMock,
+        return_value=None,
+    ), patch.object(
+        verbose_proxy_logger, "exception"
+    ) as mock_log:
+        with pytest.raises(ProxyException):
+            await handler._handle_authentication_error(
+                proxy_exc,
+                mock_request,
+                mock_request_data,
+                mock_route,
+                mock_span,
+                mock_api_key,
+            )
+
+        assert mock_log.called
+        log_message = mock_log.call_args[0][0]
+        assert "Model not allowed for this key" in log_message, (
+            f"Expected exception message in log, got: {log_message!r}"
+        )
+        assert "/v1/chat/completions" in log_message
+        assert "gpt-4o" in log_message
+
+
 @pytest.mark.asyncio
 async def test_route_passed_to_post_call_failure_hook():
     """