Solved by adding route-nopull in the .ovpn file of the ER605. Everything is working as i wanted now. Thank you.

@MR.S It seems that without the line push "redirect-gateway def1" in the server configuration file, the ER605 router does not establish the connection. What I need now is an alternative...

I found that if I remove the 'push "redirect-gateway def1"' from the server configuration the issue happen and the tunnel is not created.

It works ! Finally, I don't know what I did, I just install PIVPN as you said and I added the client as you said, and the .ovpn files it works. The tunnels was created, can't believe it.

@MR.S I’ll give it a try. Could you show me what your .ovpn files look like—both on the server side and the one used by the ER605? (Of course, without including any sensitive information.) If it...

@MR.S Hello, What do you mean by what kind of OpenVPN server I have? Sorry, I’m not very experienced, but what I’ve tried is simply installing OpenVPN and adding the configuration files. I’ve tested...