I have installed tigervnc server on many Ubuntu, CentOS, and windows systems. I cant get it to work on U-M 21.04.
I installed U-M 21.04 64bit desktop on a new laptop with a new SSD. I ran apt update to make it current. Next, I installed tigervnc-standalone-server package with apt. The default package installed reported "tigervnc-standalone-server 1.11.0+dfsg-2ubuntu0.1".
I logged in as a non-root user. I ran vncpasswd to set my password.
Next I created my ~/.vnc/xstartup according to help here:
How to Install & Configure VNC Server on Ubuntu 20.04 finding no help for U-M 21.04.
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
xsetroot -solid grey
vncconfig -iconic &
/usr/bin/mate-session --debug &
Then I run 'vncserver :1'
Then I get the following error:
New Xtigervnc server 'phil-Inspiron-15-3511:1 (painter)' on port 5901 for display :1.
Use xtigervncviewer -SecurityTypes VncAuth -passwd /home/painter/.vnc/passwd :1 to connect to the VNC server.
Session startup via '/home/painter/.vnc/xstartup' cleanly exited too early (< 3 seconds)!
Maybe try something simple first, e.g.,
tigervncserver -xstartup /usr/bin/xterm
The X session cleanly exited!
Killing Xtigervnc process ID 30379... success!
On all my other systems I dont see such messages and a session is created which I can access with my external vnc client.