Running from compiled code: How to create veth lxcbr0?

I am trying to run lxc from compiled code. Means there is no lxcbr0 created prior to running first alpine container (unprivileged) - which fails to run saying ‘lxc-user-nic failed to configure requested network: cmd/lxc_user_nic.c: 478: instantiate_ veth - Invalid argument - Failed to create veth1001_7WHT-veth1001_7WHTp’

Can someone pls help me with that? Thanks.
PS: Errors in log file.
network - network.c:lxc_create_network_unpriv_exec:2628 - Execing lxc-user-nic create /home/m1/.local/share/ lxc c1 38403 veth lxcbr0 (null)
61 lxc-start c1 20200608145202.278 ERROR network - network.c:lxc_create_network_unpriv_exec:2657 - lxc-user-nic failed to configure requested network: c md/lxc_user_nic.c: 478: instantiate_veth - Invalid argument - Failed to create veth1001_jq9G-veth1001_jq9Gp
62
63 cmd/lxc_user_nic.c: 533: create_nic: Error creating veth tunnel