Unable to connect to VNC Server using your chosen security setting. Either upgrade VNC Server to a more recent version, or select a weaker level of encryption
Saw this error message on a new installation of POP OS 18.04 LTS while trying to remotely connect to the machine.
The solution, turns out, is pretty simple.
Note: This approach disables the encryption of the VNC server on your host, make sure you protect the server through other means
Issue the following at the terminal to disable encryption, do this without SUDO:
gsettings set org.gnome.Vino require-encryption false
Try connecting again via your VNC client and you should be able to connect successfully.