Openvpn client on openpli just stopped working

After almost 2 years, the openvpn connection stopped working. The status shows active but server does not see it. I have even generated new key files which work well on other receivers but not on that particular one. I have reinstalled the openvpn a couple of times but without any success, it still does not work. Can you suggest something? I have not chance to reinstall the reliever software at the moment.