diff --git a/src/tcpcheck.c b/src/tcpcheck.c
index 8eefc4e..ef5c042 100644
--- a/src/tcpcheck.c
+++ b/src/tcpcheck.c
@@ -3450,7 +3450,7 @@
 			px->conf.args.ctx = ARGC_SRV;
 			LIST_INIT(&chk->expect.hdr.value_fmt);
 			if (!parse_logformat_string(vpat, px, &chk->expect.hdr.value_fmt, 0, SMP_VAL_BE_CHK_RUL, errmsg)) {
-				memprintf(errmsg, "'%s' invalid log-format string (%s).\n", npat, *errmsg);
+				memprintf(errmsg, "'%s' invalid log-format string (%s).\n", vpat, *errmsg);
 				goto error;
 			}
 		}