Heads up for #emacs #nolittering users, a recent commit introduced setting the `server-auth-dir`:

https://github.com/emacscollective/no-littering/commit/d62b51b2e0c828b952fd53ccbeb1816f7758a106

The commit is not part of a tagged release yet, I only discovered it because my quelpa config is not using tagged versions. If your emacsclient cannot find the server file one day, this might be the reason.