diff --git a/modules/clan/phonebox/default.nix b/modules/clan/phonebox/default.nix
index bb05411c..92ee0ed3 100644
--- a/modules/clan/phonebox/default.nix
+++ b/modules/clan/phonebox/default.nix
@@ -403,7 +403,7 @@
                     in
                     ''
                       [from-internal]
-                      exten => 999,1,Answer()
+                      exten => 99,1,Answer()
                       same  =>     n,Playback(hello-world)
                       same  =>     n,Hangup()