diff --git a/extra/autoconf/sources b/extra/autoconf/sources
index 13dd4996..399ad44a 100644
--- a/extra/autoconf/sources
+++ b/extra/autoconf/sources
@@ -1 +1 @@
-ftp://ftp.gnu.org/pub/gnu/autoconf/autoconf-2.69.tar.gz
+https://ftp.gnu.org/pub/gnu/autoconf/autoconf-2.69.tar.gz