A quick review:
thomaslauer wroteMy openvpn server is the kylemanna/docker-openvpn
I have not tried it but you say it works.
thomaslauer wrotewith windows an ios client i have no problems
Good.
thomaslauer wrotewhen i use the yealink phone i must generate a .tar file with keys an vpn.cnf
Then this is probably the step that goes wrong .. try again but copy the .tar file to windows client and unpack it then see if you get an error like the phone. You could also try this with
inline certificates in the config.
Out of curiosity, how do you install openvpn on the phone or is it pre-installed and what openvpn version is it ?