diff --git a/doc/guix.texi b/doc/guix.texi
index 5e1173b8c6..3b97674733 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -3792,7 +3792,8 @@ Getting Substitutes from Other Servers
 @end example
 
 Again this assumes @file{key.pub} contains the public key that
-@code{guix.example.org} uses to sign substitutes.
+@code{guix.example.org} uses to sign substitutes.  Make sure
+@file{/etc/guix/acl} is world-readable.
 @end enumerate
 
 Now you're all set!  Substitutes will be preferably taken from