Hi, Oshadha,
You may want to try and raise this question in Teltonika's community support forums. They might be able to provide some guidance.
But before that run through what Teltonika's wiki has to offer, and try out the configuration yourself first.
https://wiki.teltonika-networks.com/view/OpenVPN_configuration_examples
If you are to raise this question within suggested forums - provide detailed information on what you've tried so far and what exactly goes wrong.
https://community.teltonika.lt/c/teltonika-networks/5