Servers federate with specific users rather than entire other servers.
So, if a user isn't followed or interacted with by anyone on your server, and your server doesn't subscribe to any relays, then their posts won't show up. (More info: https://fedi.tips/which-posts-and-accounts-can-i-see-from-my-server/)
A couple of workarounds:
-Ask your admin about topic-based relays such as https://relay.fedi.buzz
-Follow groups on your topics, these actively push content to your server (more info: https://fedi.tips/how-to-use-groups-on-the-fediverse/).
GNU social JP is a social network, courtesy of GNU social JP管理人. It runs on GNU social, version 2.0.2-dev, available under the GNU Affero General Public License.
All GNU social JP content and data are available under the Creative Commons Attribution 3.0 license.