You pin a few coworkers to Favorites in Teams so they sit at the top of your Chat list, and then one day the Favorites grouping just is not there anymore, or a contact you were sure you pinned has quietly dropped out of it. This is almost always a display or sync issue rather than something you actually did, and it clears up with one of a few simple steps.
First, check how your chat list is sorted
Teams lets you sort the Chat list by Recent or by Most people, and separately lets you toggle whether pinned or favorite contacts are grouped at the top at all. Open the Chat list, select the sort or filter icon near the search box, and confirm Favorites or Pinned is still enabled as a grouping. It is easy to switch this by accident while cleaning up the interface.
If the grouping is on but a specific contact is missing
Right click the contact in your Chat list and check whether Pin still shows as an option to select, which means it silently became unpinned. Re-pin it and it should reappear in the Favorites group immediately. If the person does not show up in your Chat list at all anymore, search for them directly by name in the top search bar, open a chat, and pin them again from there.
If nothing is pinning correctly at all
Sign out of Teams completely and sign back in, or if you are on the desktop app, fully quit it from the system tray rather than just closing the window, since Teams keeps running in the background otherwise. Pinning data occasionally gets stuck in a local cache that a full restart clears. If it is still not sticking after that, it is worth checking Teams' own status page for a known issue affecting your region, since pinning bugs have shown up there before.
If your organization is running into repeated small friction points like this across Teams, that is often a sign it is time for a broader look at how Teams is configured and rolled out. Our Microsoft 365 and Modern Work team can help. Get in touch if you want a hand with it.