diff --git a/pkgs/applications/networking/instant-messengers/element/keytar/default.nix b/pkgs/applications/networking/instant-messengers/element/keytar/default.nix
index 550d01695ca0..362d7a096bfb 100644
--- a/pkgs/applications/networking/instant-messengers/element/keytar/default.nix
+++ b/pkgs/applications/networking/instant-messengers/element/keytar/default.nix
@@ -33,7 +33,7 @@ in stdenv.mkDerivation rec {
     chmod u+w . ./yarn.lock
     export HOME=$PWD/tmp
     mkdir -p $HOME
-    yarn config --offline set yarn-offline-mirror ${yarnOfflineCache}
+    yarn config --offline set yarn-offline-mirror $yarnOfflineCache
     ${fixup_yarn_lock}/bin/fixup_yarn_lock yarn.lock
     yarn install --offline --frozen-lockfile --ignore-platform --ignore-scripts --no-progress --non-interactive
     patchShebangs node_modules/