Local docker install and cells-sync connection

I’ve install on docker a pydio server (version 4.4.7) which is working well at https ://localhost:8080 - as presented on the github.

I’m now trying to connect a local directory to synchronize this directory with the docker server.
My scope being to check if we can use pydio as the document manager for some of our projects.

I’m facing an issue connecting with cells-sync (version 0.9.4).
When connecting to https ://localhost:8080 it returns

cannot connect to discovery endpoint: Get “https ://localhost:8080/a/config/discovery”: x509: certificate signed by unknown authority

I’ve tried to set the server without TLS using cells configure site on docker, but in this case cells-sync is opening a web page which remains blank.

How can I set-up this local installation to try Pydio?

Thank you,

After multiple trials and re-installing in docker (to have a fresh re-installation) the error on cells-sync is now different.
I’m able to give my credentials, but when selecting the folder I have the following error:

connection error: desc = "transport: Error while dialing dial tcp [::1]:41575: connectex: No connection could be made because the target machine actively refused it.

What can I do to overcome this issue?

Thank you