diff --git a/pkg/schema/field/timestamp.go b/pkg/schema/field/timestamp.go
index cc13bbea2dc0b657e20157a0bed3c9640b64ce0b..7f89aefc1982e12996f9307129bc396e501cecb9 100644
--- a/pkg/schema/field/timestamp.go
+++ b/pkg/schema/field/timestamp.go
@@ -51,7 +51,7 @@ func toTimestamp(i interface{}) (interface{}, error) {
 	case uint32:
 		return int64(v), nil
 	default:
-		return 0, fmt.Errorf("unsupported value type: \"%T\"", i)
+		return nil, fmt.Errorf("unsupported value type: \"%T\"", i)
 	}
 }