diff --git a/src/interfaces/libpq/fe-protocol3.c b/src/interfaces/libpq/fe-protocol3.c
index 7222adabba..32b66d561c 100644
--- a/src/interfaces/libpq/fe-protocol3.c
+++ b/src/interfaces/libpq/fe-protocol3.c
@@ -1420,20 +1420,21 @@ pqGetNegotiateProtocolVersion3(PGconn *conn)
 	}
 
 	if (their_version < conn->pversion)
-		appendPQExpBuffer(&conn->errorMessage,
-						  libpq_gettext("protocol version not supported by server: client uses %u.%u, server supports up to %u.%u\n"),
-						  PG_PROTOCOL_MAJOR(conn->pversion), PG_PROTOCOL_MINOR(conn->pversion),
-						  PG_PROTOCOL_MAJOR(their_version), PG_PROTOCOL_MINOR(their_version));
+		libpq_append_conn_error(conn, "protocol version not supported by server: client uses %u.%u, server supports up to %u.%u",
+								PG_PROTOCOL_MAJOR(conn->pversion), PG_PROTOCOL_MINOR(conn->pversion),
+								PG_PROTOCOL_MAJOR(their_version), PG_PROTOCOL_MINOR(their_version));
 	if (num > 0)
+	{
 		appendPQExpBuffer(&conn->errorMessage,
-						  libpq_ngettext("protocol extension not supported by server: %s\n",
-										 "protocol extensions not supported by server: %s\n", num),
+						  libpq_ngettext("protocol extension not supported by server: %s",
+										 "protocol extensions not supported by server: %s", num),
 						  buf.data);
+		appendPQExpBufferChar(&conn->errorMessage, '\n');
+	}
 
 	/* neither -- server shouldn't have sent it */
 	if (!(their_version < conn->pversion) && !(num > 0))
-		appendPQExpBuffer(&conn->errorMessage,
-						  libpq_gettext("invalid %s message"), "NegotiateProtocolVersion");
+		libpq_append_conn_error(conn, "invalid %s message", "NegotiateProtocolVersion");
 
 	termPQExpBuffer(&buf);
 	return 0;