[edit interfaces openvpn vtun0]
vyos@vyos# delete server client client1 ip 
[edit interfaces openvpn vtun0]
vyos@vyos# commit
[ interfaces openvpn vtun0 ]
Traceback (most recent call last):
  File "/usr/libexec/vyos/conf_mode/interfaces-openvpn.py", line 1037, in <module>
    verify(c)
  File "/usr/libexec/vyos/conf_mode/interfaces-openvpn.py", line 888, in verify
    if not ip_address(client['ip']) in ip_network(subnet):
  File "/usr/lib/python3.7/ipaddress.py", line 54, in ip_address
    address)
ValueError: '' does not appear to be an IPv4 or IPv6 address

[[interfaces openvpn vtun0]] failed
Commit failed