Only two containers at a time?

What might be the reason I cannot run more than two containers at a time?

Could you describe what happens when you try to ‘run’ more containers?

Do you mean you can’t launch a third? Or it launches but doesn’t start?

Is this LXD or LXC?

@tomp @johnrm
Thank you for replying to my question.
This was the output of lxc-start -n container-name -F

lxc-start:  server: network.c: lxc_create_network_unpriv_exec: 2990 Lxc-user-nic failed to configure requested network: cmd/lxc_user_nic.c: 1206: main: Quaternary reached
lxc-start: ubuu-server: start.c: lxc_spawn: 1843 Failed to create the network
lxc-start: Ubuntu-server: start.c: __lxc_start: 2074 Failed to spawn container “Ubuntu-server”
306 The container failed to stare

This was the output of /etc/lxc/lxc-usernet

sherab veth lxcbr0 2 
unpriv veth lxcbr0 10

I finally changed the sherab veth lxcbr0 2 to 10 and now all the containers work.
Thank you