Hello,
Regarding this issue of yours, I would recommend you referring to this link for more information: OpenVPN configuration examples - Teltonika Networks Wiki (teltonika-networks.com)
It would be best if you provide us the whole details of what are you trying to achieve and how did you set up everything? First of all, I want to remind you that you must have at least 1 Public IP address for the OpenVPN Server to establish an OpenVPN network.
Regards,
Mellow
