I have been using the .onion address for my Electrum server for a while now. This afternoon it stopped connecting, giving me the message "socks: host unreachable. check if the proxy server is running."
Is Sparrow running on a separate machine?
If so, there's nothing to configure there but to set your EPS's correct .onion address and port since it'll automatically start its own integrated Tor client when connecting to your server.
In that case, look for Tor issues in your machine where EPS is installed.