"error: the plugin does not support import capability" when attempting to import openvpn config file

My setup

I also had the same issue, trying to import on an Ubuntu 16.04 client a .ovpn file produced by a home pritunl server.

The .ovpn file contained comment lines (#) as well as inline certificates (<ca>, <tls-auth>, <cert>, <key>). And there was no apparent reason to remove comments or keys. This same .ovpn had already been successfully imported into the Kubuntu 16.04 network manager, with only a warning about reneg-sec being too high; A clue to import issues on Ubuntu 16.04.

Solving the OP's errors

1. The reneg-sec value is too high and encounters known import bug:

   reneg-sec 2592000
   

   Comment it out or use default value 3600.

   #reneg-sec 2592000
   

   This value can be re-set from Advanced settings in VPN config tab under:

   

2. The config had two remote definitions:

   remote hostname.org 14195 udp6
   remote hostname.org 14195 udp
   remote-random
   

   Try with only one:

   #remote hostname.org 14195 udp6
   remote hostname.org 14195 udp
   #remote-random
   

After these two modifications, there were no import errors.

Further issue with remote configuration

Although there was no import error any more, the remote was not imported properly, i.e. the port and protocol were not properly parsed, so I had to further break the remote directive down in the .ovpn file as follows

    remote hostname.org
    port 14195
    proto udp

Summary

My .ovpn file contained comments as well as inline certificates, etc.. After reading some other posts, I thought the problem lied in the inline files or the comments, so I split the inline certificates and keys into separate files and removed all comments.

So in the end, after applying the above fixes, the .ovpn file with the inline keys and comments was imported.

The issue for me was the following line in my .ovpn file:

route remote_host 255.255.255.255 net_gateway

Commenting out this line allowed me to import the connection.

I also have Ubuntu 16.04, and the same problem occurs. The solution is not a very good solution, because you need another computer already connected with the VPN.

Check that you have already installed openvpn and network-manager, from the terminal:

$ sudo apt install openvpn network-manager-openvpn network-manager-openvpn-gnome
$ sudo systemctl restart network-manager

In general, this should work, but in very few cases (and i don't know why - i suppose that's probably a bug) a .ovpn can't be imported.

So, follow theses steps:

1. On the computer that already have a created connection with the VPN, select the vpn connection

2. make empty the password

3. click on export button

At this point, you'd have a ".conf" file.

4. open the ".conf" file and edit any parts that reference files on your computer if exists

5. In your computer, create a new connection with the ".conf" file.