outlook will not sync on android

Reset the affected account inside Outlook for Android to refresh its local data and retrieve the missing recent messages.

Reset the account

1. Force-close Outlook, reopen it, and check the Inbox once more.
2. In Outlook, tap your profile picture in the upper-left corner.
3. Tap Settings (gear icon).
4. Select the email account that is not updating.
5. Tap Reset Account.
6. Allow Outlook to restart, then open the Inbox and wait for synchronization to complete.

Microsoft recommends this procedure when Outlook for Android displays incomplete or incorrect data.^1^

If resetting does not restore the messages

Remove only the account from Outlook and add it again:

1. Open Outlook → Settings.
2. Select the affected account.
3. Tap Delete Account, then Delete From This Device.
4. Return to Settings → Add Email Account and sign in again.
5. Keep Outlook open until the Inbox repopulates.

Deleting it from this device removes the local Outlook connection; it does not instruct the mail service to delete the mailbox. Microsoft documents re-adding the account as the next step when account reset does not work.^2^

Conditional check for a work or school account

If this is a Microsoft 365 work or school account that uses Microsoft Authenticator or Company Portal, Android power restrictions can prevent Outlook from completing authentication or syncing:

1. Open the phone’s Settings → Apps.
2. Select Authenticator or Company Portal.
3. Open Battery and disable battery optimization or select the option permitting background activity.
4. Turn off Android power-saving mode temporarily.
5. Open Authenticator or Company Portal first, and then open Outlook.

Microsoft specifically identifies these restrictions as a possible cause when Outlook for Android cannot synchronize new Microsoft 365 messages.^3^

If the mailbox still does not update after re-adding it, use Outlook → Settings → Help & Feedback → Contact Support. For a work or school mailbox, contact the Microsoft 365 administrator as well.

References

1. How do I clear the cache or locally reset/refresh the client/app?
2. Outlook app
3. Failed to add Microsoft 365 account or cannot sync new messages with your existing Microsoft 365 account? | Microsoft Support