Dear,
With new release we don't have anymore Administration part to manage BC365 on-premise. Total madness. Now I have installed 21.0.53794.0 version but I cannot add any instance. I have added via shell two instances, edit the config with txt or with Service Tier Administration application, but no success. I have three different databases with all permissions. This is so stupid move to kill mmc console. I have also tried with Set-NAVServerConfiguration but no luck. Does any have tried to add more that one instance with this version?