I can’t thanks you enougth.
I had my api. certificats that expired, and managed to have the server up again using your commands ( just not in the “vpn” directory, but in the “root” one)
Two things to add: easyrsa need the index.txt, so just add this command after renaming it:
touch index.txt
And the OPENBALENA_VPN_SERVER_CRT and OPENBALENA_VPN_SERVER_KEY are found in the config/activate file
Thanks again