Error getting fee estimates when connecting to private Electrum Server (Fulcrum)

I am trying to connect my machine via Tor to my Bitcoin Full Node (Fulcrum running there):

The Fulcrum logs are recognizing the connection correctly when I am starting to connect from the remote machine via Tor:

I checked the listener Ports on the Full Node machine and the remote machine, they are correctly opened:

But then the connection is break up and I am getting the following error on the remote machine in the sparrow logs:

Can anyone help?

cculianu / Fulcrum