diff --git a/nixos/modules/services/networking/prosody.nix b/nixos/modules/services/networking/prosody.nix
index a37ef98caec..25b7d6dbeba 100644
--- a/nixos/modules/services/networking/prosody.nix
+++ b/nixos/modules/services/networking/prosody.nix
@@ -228,6 +228,7 @@ let
 
   createSSLOptsStr = o: ''
     ssl = {
+      cafile = "/etc/ssl/certs/ca-bundle.crt";
       key = "${o.key}";
       certificate = "${o.cert}";
       ${concatStringsSep "\n" (mapAttrsToList (name: value: "${name} = ${toLua value};") o.extraOptions)}