Add the user 'it' to the 'snap_daemon' group:

A simple web search for "ubuntu add a user to a group" tells

To add a user to a group, open the Terminal, then type "sudo usermod -a -G examplegroup exampleusername" into the window. Replace "examplegroup" and "exampleusername" with the group and username you want to modify.

In your case that is:
sudo usermod -a -G snap_daemon it

this one i already use but not working

 sunbeam cluster bootstrap --accept-defaults:
I try this command after showing below error,

Error: Insufficient permissions to run sunbeam commands

Add the user 'it' to the 'snap_daemon' group:

After this, reload the user groups either via a reboot or by running 'newgrp snap_daemon'.

What exactly are you trying to do?

For the instruction "sudo usermod -a -G snap_daemon it" you answered: "this one i already use but not working"

"Not working" in which sense? Did you receive an error message? Was the user added to the group? What happened?

Maybe the root cause of your problem is something completely different, e.g. something like https://bugs.launchpad.net/snap-openstack/+bug/2027900/comments/4

I installing the open stack.