Can not connect to webconsole server

[DenEric]

I have the webconsole version 2.4.1 running on the spigot minecraft server.
And I have the client configured on a nginx webserver the same machine.
I can communicate with the server:
./websocat.aarch64-unknown-linux-musl ws://localhost:5555
{"status":401,"statusDescription":"Login Required","message":"Verbinding gestart, wachtend op inloggen"}

but if I try to configure a server on the console I get a connection error:

Connection was lost with the server. This can be caused by:
Server was closed intentionally.
Port is not opened on your host. In this case, troubleshoot using a port checker and recheck your firewall or router

Any assistance would be appreciated