diff --git a/tests/integrations/mcs/tso/api_test.go b/tests/integrations/mcs/tso/api_test.go
index 327254184620..630e6c0de625 100644
--- a/tests/integrations/mcs/tso/api_test.go
+++ b/tests/integrations/mcs/tso/api_test.go
@@ -214,6 +214,7 @@ func TestForwardOnlyTSONoScheduling(t *testing.T) {
 	tc.WaitLeader()
 	leaderServer := tc.GetLeaderServer()
 	re.NoError(leaderServer.BootstrapCluster())
+	ttc.WaitForDefaultPrimaryServing(re)
 
 	urlPrefix := fmt.Sprintf("%s/pd/api/v1", pdAddr)