diff --git a/apigee/edge_client_test.go b/apigee/edge_client_test.go
index 2e44561..f7bd34f 100644
--- a/apigee/edge_client_test.go
+++ b/apigee/edge_client_test.go
@@ -283,7 +283,7 @@ func TestMutualTLSNoCerts(t *testing.T) {
 	}
 
 	_, err = c.Do(req, nil)
-	testutil.ErrorContains(t, err, "remote error: tls: bad certificate")
+	testutil.ErrorContains(t, err, "remote error: tls: certificate required")
 }
 
 func newMutualTLSServer() *httptest.Server {