Timelines get new posts at the times your admin sets. By default, that is every 24 hours. Until then, you see the posts from the last time.
How refresh works
The app keeps a saved copy, called a cache. When its set time ends, the next view starts a refresh. Old posts may stay on screen while new posts load. They may also stay if the refresh fails. Your admin can set this time from 1 to 168 hours.
What to check
-
Open the source on X. Check whether it has new public posts.
-
Ask your admin how long the app keeps saved posts.
-
If that time has passed and you see an error, follow Fix a problem.
See Change timeline refresh and cache settings. Shorter times can use more API credits. X may avoid repeat charges within a day. That billing rule does not make the posts on your page newer.