Not sure if this is still an issue, but here is what I did and it work without issue:
I have a MT300A and have a PureVPN account. They have Howto’s for a number of routers, but not openwrt. I went to their DD-WRT howto (https://support.purevpn.com/openvpn-script-method-for-dd-wrt), and downloaded their OpenVPN files. What I got was a zip with the ca.crt, Wdc.key, and folders of ovpn file (TCP and UDP). I simply uploaded this zip in the basic OpenVPN GUI, entered my username and password, and it just worked. I have been using UDP, but have not tried TCP.
Well, I have tried all the servers in the list and it is still not working :-D. So I am kind of left out and i would like to still be able to use it. What is found weird is that it was working in Taiwan very good and once got I got here nothing works. I imagine is something about ports or routing it ?
ok this is just my 5 cent,but here is what i gather so far from learning openVPN
its best to buy cheap vps rather than questionable openvpn provider
well its not like they all are not worth it,but most of them are not worth it.
by using VPS cons is you need more time and knowledge to set it up, but continue reading.
If your network block the openvpn service in level 2 than you are out of luck, but if they only block port list then you always can tweak your openvpn server to use tcp 80 / 443 as openvpn port
this is why in point 1 i suggest using vps, although i have heard some good openvpn vendor already have this kind of configuration
I use Airvpn. Wish they had more server locations in Asia (especially in Japan) and South America but their config generator makes using the GL router brain dead easy. Just load the zip file and that’s it. There is literally nothing to configure you just scroll to the server you want and that’s it. I hate vpns that require that you install firmware/software.
any update here, having same issue, that purevpn (openvpn) is not working with 300m.
OpenVPN 2.4.3 mips-openwrt-linux-gnu [SSL (OpenSSL)] [LZO] [LZ4] [EPOLL] [MH/PKTINFO] [AEAD] library versions: OpenSSL 1.0.2k 26 Jan 2017, LZO 2.09 WARNING: No server certificate verification method has been enabled. See How To Guide: Set Up & Configure OpenVPN Client/server VPN | OpenVPN for more info. Cannot open file key file ‘Wdc.key’: No such file or directory (errno=2) Exiting due to fatal error
I have loaded the zip file from purevpn site and it has cert and key file there with open vpn config files.