Is it possible to add existing keys to Outline VPN server?

I’ve got a server hosting Outline VPN. Due to some circumstances I had to reinstall OS on the server. I had a lot of clients, and I would like to just add existing access keys to new server instead of creating new ones and sending them to every client manually. Is it possible to do that via the manager?

Not via the manager but you can do that by saving (and restoring arfter the OS reinstall) the /opt/outline/persistent-state directory on your host