diff --git a/config-daemon.ac b/config-daemon.ac
index 803eb5369963c4e76fbebfdc3aaedcbe84bf2f5a..f66f31269dfb34e6ac90626f8bc78b75f43db94f 100644
--- a/config-daemon.ac
+++ b/config-daemon.ac
@@ -113,10 +113,10 @@ if test "x$guix_build_daemon" = "xyes"; then
   dnl Determine the appropriate default list of substitute URLs.
   GUILE_MODULE_AVAILABLE([have_gnutls], [(gnutls)])
   if test "x$have_gnutls" = "xyes"; then
-    guix_substitute_urls="https://mirror.hydra.gnu.org https://hydra.gnu.org"
+    guix_substitute_urls="https://mirror.hydra.gnu.org"
   else
     AC_MSG_WARN([GnuTLS is missing, substitutes will be downloaded in the clear])
-    guix_substitute_urls="http://mirror.hydra.gnu.org http://hydra.gnu.org"
+    guix_substitute_urls="http://mirror.hydra.gnu.org"
   fi
   AC_MSG_CHECKING([for default substitute URLs])
   AC_MSG_RESULT([$guix_substitute_urls])
diff --git a/guix/store.scm b/guix/store.scm
index 276684e2fbe85f4b414b8e623eeb771773344428..9f409b42097e613ed2c29804f6c02114a676cd38 100644
--- a/guix/store.scm
+++ b/guix/store.scm
@@ -510,7 +510,7 @@ (define %default-substitute-urls
   (map (if (false-if-exception (resolve-interface '(gnutls)))
            (cut string-append "https://" <>)
            (cut string-append "http://" <>))
-       '("mirror.hydra.gnu.org" "hydra.gnu.org")))
+       '("mirror.hydra.gnu.org")))
 
 (define* (set-build-options server
                             #:key keep-failed? keep-going? fallback?