VPN Certs seems to be expired

Hallo @ab77 ,
thank you for the respond. I would like to try to follow your suggestions. I checked the time on the different devices and containers with the simple command date. This is the result.

balenaOS - Wed Mar 3 07:14:06 UTC 2021
supervisor - Wed Mar 3 07:14:48 UTC 2021

open-balena host os - Wed Mar 3 08:19:30 CET 2021
vpn container - Wed Mar 3 07:20:19 UTC 2021

So beside the timezone differenc everything seems fine.
But I digged deeper and found under config/certs/vpn/issued/vpn.<server_domain>.crt the vpn cert, that was created with the quickstart script. And it seems, that this certificate expired on the 6. february. So my question is can I renew that cert and if yes what changes I have to do on the clients as well?

Other maybe a little naive question. Is it possible to use the same CA and CERT for vpn that I use for the Root? So that value, that is used for OPENBALENA_ROOT_CA can I use that for OPENBALENA_VPN_CA and OPENBALENA_ROOT_CRT for OPENBALENA_VPN_CRT and so on?