I am on a Windows machine, and tried to access through VNC into a Linux server running ubuntu. I followed this tutorial https://www.cyberciti.biz/faq/install-and-configure-tigervnc-server-on-ubuntu-18-04/ and installed a VNC server on the server, and a viewer on the client (I use TightVNC viewer and vncserver on the server). I can manage to connect successfully on the server. However, in the login screen of the gnome session, I cannot input anything, so I can't login. That's what it says (my name deleted): Notice that the keyboard input is sent to the server (that is, I am not in view only mode), as I can have access to this screen from the gnome welcome screen by pressing the spacebar. However, when I write in the field, I don't see anything. The "authentication error" message is there since the beginning.
I have tried with other VNC viewers with exactly the same results. Any idea?