By setting an allow list you’ve blocked every other instance not in your list, just compare this post for example to the original on lemmy.ml or the copy at lemmy.world for example
Allowlist: Explicitly list instances to connect to. BlockList: Explicitly list instances to not connect to. Federation is open to all other instances. Open: Federate with all potential instances.
Federation is enabled by default. You can add allowed and blocked instances, by adding a comma-delimited list in your instance admin panel. IE to only federate with these instances, add: enterprise.lemmy.ml,lemmy.ml to the allowed instances section.