Outlook Mobile App Not Syncing Email or Calendar

Published ✓ Verified ⏱️ 2 min read March 1, 2026 · by Ryan Bennett

Your Outlook app on your phone or tablet has stopped pulling in new mail or calendar events.

Why: Most mobile sync problems trace back to one of three things: a stale app session, the wrong account type, or missing permissions. Work through them in order before deleting anything.

Fix 1: Check the account type

If you added the account as IMAP or POP, that’s the root cause for calendar and contacts. IMAP and POP can only sync email, not calendar or contacts. To sync everything, the account must use Exchange ActiveSync (or a Microsoft 365 / Exchange account).

Open the app’s Settings, tap the account, and check the type listed. If it shows IMAP/POP, you’ll need to remove it and re-add it as an Exchange account.

Fix 2: Confirm permissions

The app needs the device’s permission to reach your calendar and contacts:

iOS: Settings > Outlook, then turn on Contacts and Background App Refresh.
Android: Settings > Applications > Outlook and make sure Contacts is enabled.

Fix 3: Reset the account, then restart

In the Outlook app, open Settings, tap the affected account, and choose Reset Account. After it resyncs, close and reopen the app. If that fails, power the device completely off, wait a few seconds, turn it back on, and let the mailbox sync again.

Fix 4: Remove and re-add the account

If resetting doesn’t help, in Settings tap the account and choose Delete Account (Delete From This Device), then add it back. When re-adding, make sure it comes in as Exchange, not IMAP or POP.

FAQ

Email syncs but calendar doesn’t. That’s the classic IMAP/POP symptom, see Fix 1. Re-add the account as Exchange ActiveSync.

Everything was working until recently. Check for a service outage and for an app update in the App Store or Google Play, then reset the account.

Will resetting delete my mail? No. Reset re-downloads the mailbox from the server; your messages and events stay on the server.

Sources: Can’t sync calendar and contacts with my phone or tablet, Troubleshoot Outlook mobile issues