@ChuckyP 

There are problems with tp-link routers if the server is not installed with OpenVPN 2.4 or older client compatibility, tp-link is unable to connect if the server is newer than verion 2.4. it took a long time and many installations before I realized that I had to install the server this way. I had a choice to install server with OpenVPN 2.4 and older client support and when I do that router connect up..

I'm no expert on OpenVPN so I use pivpn, (OpenVPN for dummies) easy installation

  @MR.S 

This might explain the issues I'm describing in this thread. Did you actually install 2.4 server version?

I tried the pivpn script you mentioned on my Debian Bullseye VPS. But it installed 2.6.x server.

Got some certificate issue trying to connect (tried from different client).

  @flips01 

when I installed I chose 2.4 or older compatibility, this was a choice I got during the installation. don't remember all the details in the screenshots

  @flips01 

I did a quick test on an ubuntu server I have, here are the changes that are not deafult

If you have ER8411 you have to install with TCP not UDP.

Create user with nopass. and import ovpn file in router.

  @ChuckyP 

Ah, thanks! It seems the trick (for my ER605v2) was to select TCP ... (Well, now I see some activity in the server log, not really seeing response yet, but hey ... progress, will dig a bit more soon.) :-)

  @ChuckyP well, it's not working, but something is registering when the Omada ER605v2 tries to connect:

2023-07-18T01:02:22.251874+02:00 myserver ovpn-server[598]: TCP connection established with [AF_INET](redacted IP):6662
2023-07-18T01:02:23.191249+02:00 myserver ovpn-server[598]: (redacted IP):6662 TLS: Initial packet from [AF_INET](redacted IP):6662, sid=5a79cb4a b43c1349
2023-07-18T01:02:23.494572+02:00 myserver ovpn-server[598]: (redacted IP):6662 Connection reset, restarting [-1]
2023-07-18T01:02:23.495252+02:00 myserver ovpn-server[598]: (redacted IP):6662 SIGUSR1[soft,connection-reset] received, client-instance restarting

So, not working, but getting closer. I tried fiddling with settings, but OpenVPN is not really something I know very well.

I wish the Omada GUI will get better logging/debugging for what's happening/not happening ... Or also Wireguard client-to-server setup.

Edit:

Seems it was multiple challenges: I fixed NTP on the server, reinstalled everything, then ended up with some no common data ciphers error.

So I added this to the server config file:

  data-ciphers AES-256-GCM:AES-128-GCM:AES-256-CBC
  data-ciphers-fallback AES-256-CBC
  tls-version-min 1.0

So now I have connection. I do have to setup some routing or something, but connection is made.

And it actually shows up under Insight --> VPN clients for OpenVPN

Hi everyone, thanks for all the tips. I do wish TP-Link would weigh in on this and fix connectivity to modern versions of OpenVPN 2.4+... 

I will try Pivpn as suggested.