diff --git a/custom-add-ons.md b/custom-add-ons.md
index 61201e0..8dc318f 100644
--- a/custom-add-ons.md
+++ b/custom-add-ons.md
@@ -30,7 +30,7 @@ services.bitcoind.package = mkForce config.nix-bitcoin.pkgs.bitcoind;
 The code for CLN for BTCpayserver backend is as follows:
 
 ```nix
-services.btcpayserver.lightningBackend = mkForce clightning;
+services.btcpayserver.lightningBackend = mkForce "clightning";
 ```