diff --git a/src/mux_fcgi.c b/src/mux_fcgi.c
index 1db86460d..5685ba9c4 100644
--- a/src/mux_fcgi.c
+++ b/src/mux_fcgi.c
@@ -3532,7 +3532,7 @@ static void fcgi_detach(struct conn_stream *cs)
 	fcgi_strm_destroy(fstrm);
 
 	if (!(fconn->conn->flags & (CO_FL_ERROR|CO_FL_SOCK_RD_SH|CO_FL_SOCK_WR_SH)) &&
-	    !(fconn->flags & FCGI_CF_KEEP_CONN)) {
+	    (fconn->flags & FCGI_CF_KEEP_CONN)) {
 		/* Never ever allow to reuse a connection from a non-reuse backend */
 		if ((fconn->proxy->options & PR_O_REUSE_MASK) == PR_O_REUSE_NEVR)
 			fconn->conn->flags |= CO_FL_PRIVATE;