Microsoft 365 on your iPhone is stuck, stale, or refusing to pull in new mail, files, and calendar changes, and that makes the app feel broken even when your account is fine. This article walks you through the fix that clears the block, gets sync moving again, and shows you when the problem is in the iPhone, the app, or your Microsoft account.
Quick fix
The fastest fix is to force Microsoft 365 back into a clean sign-in state: close the app, turn off Low Power Mode, open the app again, and sign out and back in from the account settings inside the app. On iPhone, stale sync almost always comes from a paused background process, a stuck token, or a blocked network permission, and a fresh sign-in clears the most common one.
Why this happens
Microsoft 365 on iPhone depends on a live connection between the app, your Microsoft account, and iOS background activity. If any part of that chain gets stuck, the app stops refreshing new content even though the account still exists and old data still shows up. The most common triggers are Low Power Mode, disabled Background App Refresh, a bad cached sign-in, or a network change that interrupted syncing in the middle of a session.
How to fix it
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Force-quit Microsoft 365 and reopen it.
Swipe up from the bottom of the screen and pause, then swipe the Microsoft 365 app off the app switcher. Reopen it from the Home Screen or App Library. This clears a stuck foreground session, and success looks like the app loading your recent files, mail, or calendar without hanging on the old view. -
Turn off Low Power Mode.
Open Settings → Battery and switch Low Power Mode off. Low Power Mode cuts background activity and delays refresh, which blocks Microsoft 365 from pulling changes promptly. After you turn it off, wait a minute and check whether new items appear without manually refreshing. -
Check Background App Refresh for Microsoft 365.
Go to Settings → General → Background App Refresh and make sure it is turned on for the iPhone and for Microsoft 365. If the toggle for Microsoft 365 is off, the app gets fewer background updates and can appear frozen on older content. Turn it on, reopen Microsoft 365, and then switch to another app and back again to confirm the content updates. -
Sign out of Microsoft 365 and sign back in.
Open Microsoft 365, tap your profile icon, then choose Settings or Accounts and sign out of the affected account. Sign back in with the same Microsoft email and password, then complete any verification prompt. This is the single best fix for a broken sync token, and success looks like fresh mail, documents, or calendar changes loading after the new login finishes. -
Refresh the app’s access to your account and network.
Open Settings → Microsoft 365 and confirm that Cellular Data is on if you use mobile data. Then go to Settings → Wi‑Fi, tap the connected network, and forget it only if the app fails on one network but works on another. If you use a VPN, turn it off and test again, because Microsoft 365 can stall when a VPN blocks Microsoft servers or rewrites the connection. -
Remove and reinstall Microsoft 365.
Press and hold the app icon, tap Remove App, then delete it from the iPhone. Reinstall Microsoft 365 from the App Store, open it, and sign in again with the same account. This resets the local app cache, and if the app updates normally after reinstalling, the problem was in the saved data on the phone rather than your Microsoft account. If you also use Outlook, the same stale-cache pattern can affect saved account data in the mail app, so a clean reinstall fixes both sides of the sync chain.
Common error messages
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“We couldn’t refresh your data.”
The app reached Microsoft 365 but could not complete the sync request, which points to a network block, bad token, or background refresh failure. -
“Account requires attention.”
Microsoft 365 lost the saved sign-in state and needs you to reauthenticate before it can pull new changes. -
“Something went wrong while syncing.”
The app started a sync and then hit a connection or credential problem before it finished. -
“No internet connection.”
Microsoft 365 is not getting a usable network path, even if other apps still seem online.
When this means it’s a bigger problem
If Microsoft 365 still will not update after a fresh sign-in, a reinstall, and testing on a different Wi‑Fi network, the problem is no longer your iPhone cache or settings. The clearest sign of a larger issue is that the same account fails to update on another device, or that every Microsoft app tied to the same account shows the same stale data. At that point, the issue sits on the account side or the Microsoft service side, and you need official support to check the account status and sync logs.
Helpful answers
Frequently Asked Questions
How long should Microsoft 365 take to show new mail, files, or calendar changes after I fix it?
Once the sync block is cleared, new content appears within a minute of reopening Microsoft 365 or signing back in. If you switch away from the app and return, the refreshed data should load immediately. If nothing changes after a full minute and another manual refresh, the app is still blocked.
Will reinstalling Microsoft 365 delete my Microsoft account data?
No. Reinstalling removes the app from your iPhone, not your Microsoft 365 cloud data. Your mail, files, and calendar entries stay tied to your account. What you lose is the local cache and saved app state on the phone, which is exactly what you want when the sync layer is stuck.
What if Microsoft 365 still will not update after I sign out and sign back in?
That points to a deeper network, account, or service issue. Test Microsoft 365 on a different Wi‑Fi network and with any VPN turned off. If the same account stays stale on another device too, the problem is no longer on your iPhone. Move to Microsoft 365 Sync Problems for the next layer of troubleshooting.
Does Background App Refresh need to stay on for Microsoft 365 to keep updating?
Yes. If Background App Refresh is off for Microsoft 365, the app loses the background activity it uses to pull in new changes. You can still open the app manually, but the content will lag and look stale. Keeping it on gives Microsoft 365 a reliable path to refresh outside the foreground.
Can I undo the fix and go back to the old app setup?
Yes. You can turn Low Power Mode back on, disable Background App Refresh for Microsoft 365, reconnect to your previous Wi‑Fi network, and sign in with the same account again. Those changes are reversible. If the old behavior returns, the sync block is tied to one of those settings or to the local app cache.