diff --git a/src/session.c b/src/session.c
index d87813e37..e5b76eb3a 100644
--- a/src/session.c
+++ b/src/session.c
@@ -1888,7 +1888,7 @@ struct task *process_session(struct task *t)
 
 		/* Now we can add the server name to a header (if requested) */
 		/* check for HTTP mode and proxy server_name_hdr_name != NULL */
-		if ((s->flags && SN_BE_ASSIGNED) &&
+		if ((s->flags & SN_BE_ASSIGNED) &&
 			(s->be->mode == PR_MODE_HTTP) &&
 			(s->be->server_id_hdr_name != NULL)) {