To enable TUN/TAP on your vps go to the SolusVM Control Panel, Click Manage > Settings > Enable TUN/TAP.

check if TUN/TAP is working correctly:

1: # cat /dev/net/tun

The output should be:
2:# cat: /dev/net/tun: File descriptor in bad state

Note: Enabling TUN/TAP also enables certain settings required for IPsec and dnsmasq.