vyos@RTR1:~$ reset vpn remote-access all 
Traceback (most recent call last):
  File "/usr/libexec/vyos/op_mode/reset_vpn.py", line 86, in <module>
    main()
  File "/usr/libexec/vyos/op_mode/reset_vpn.py", line 77, in main
    terminate_sessions(username=args.username, interface=args.interface, protocol=args.protocol)
  File "/usr/libexec/vyos/op_mode/reset_vpn.py", line 40, in terminate_sessions
    run(pptp_cmd, stdout=DEVNULL, stderr=DEVNULL)
  File "/usr/lib/python3/dist-packages/vyos/util.py", line 65, in run
    decode=decode,
  File "/usr/lib/python3/dist-packages/vyos/util.py", line 48, in popen
    tmp = p.communicate(input, timeout)[0].strip()
AttributeError: 'NoneType' object has no attribute 'strip'