when i access any one of my domains in my server, through port 8080, appears: and this appears as pure text... this is a mistake? this is something that I did wrong?
This is no mistake, port 8080 is https only. So the error does not depend on the domain you used to access the server, the error appears because you used http:// and not https:// and it explains that you shall use https to connect to te service on that port.
