[SOLVED]WorldGuard API problemz, adding owner disappears on server restart

I'm developing a plugin that shall give users owner rights to the region they're standing in when they type a command.
Now, it works. I type the command, I'm the owner of the region. All is joy.

But then I restart the server, and all of a sudden someone has taken my rights from me!
Any idea of what I should do?

Code:

private void setOwner(Player player, RegionManager rm, String regionName) {
        DefaultDomain domain = new DefaultDomain();
        domain.addPlayer(player.getName());
     
        rm.getRegion(regionName).setOwners(domain);
        player.sendMessage("Region claimed!");
    }

SOLVED:

added
try {
rm.save();
} catch (ProtectionDatabaseException e) {
e.printStackTrace();
}
and updated plugin on server.