diff --git a/src/interfaces/libpq/fe-protocol3.c b/src/interfaces/libpq/fe-protocol3.c
index 840e018cd18..78ffb1025d0 100644
--- a/src/interfaces/libpq/fe-protocol3.c
+++ b/src/interfaces/libpq/fe-protocol3.c
@@ -1560,7 +1560,8 @@ pqGetNegotiateProtocolVersion3(PGconn *conn)
 	 */
 	if (expect_test_protocol_negotiation && !found_test_protocol_negotiation)
 	{
-		libpq_append_conn_error(conn, "server did not report the unsupported `_pq_.test_protocol_negotiation` parameter in its protocol negotiation message");
+		libpq_append_conn_error(conn, "server did not report the unsupported \"%s\" parameter in its protocol negotiation message",
+								"_pq_.test_protocol_negotiation");
 		goto failure;
 	}