SSH Login as openvpnas user 

$ ssh openvpnas@<open-vpn-server-ip>
$ cd /usr/local/openvpn_as/scripts/ # Go to OpenVPN AS Scripts directory
$ sudo ./sacli --user USERNAME GoogleAuthRegen # Replace USERNAME with username to get a new Google Authenticator Secret 

Source: https://forums.openvpn.net/viewtopic.php?t=15366