Outlook calendar and contacts not syncing anymore with Calendar and contacts on my Android phone

The current setup is the root cause: Gmail added to Outlook is typically an IMAP account, and IMAP/POP do not sync calendar or contacts. They sync email only. That is why Outlook classic on Windows can show Gmail email, but the Android Calendar and Contacts apps cannot reliably sync Outlook calendar/people data from that Gmail account.

For the Android side, use this path:

1. In Outlook for Android, open Settings > Accounts > select the affected account.
2. Check the account type shown at the top.
   • If it is IMAP or POP, calendar and contacts sync is not supported for that account.
3. If it is not IMAP/POP, tap Reset Account.
4. If reset does not help, go to Settings > select the account > Delete Account > Delete From This Device, then add it again.
5. In Outlook for Android, go to Settings > Contacts > Sync Contacts and turn on sync for the accounts that should export contacts to the phone.
6. On Android, go to Settings > Apps > Outlook > Permissions and make sure access to Contacts and accounts is allowed.
7. In Outlook for Android, go to Calendar, tap the calendar icon or avatar in the upper-left, and make sure the correct calendar is selected with a checkmark.

Important limitation for the built-in Samsung/Android apps:

• If the account is added as IMAP, the phone’s Calendar and Contacts apps will not sync calendar/contacts from it.
• In Samsung Email, if an account is IMAP, it must be removed and re-added as Exchange or Outlook.com for calendar/contact sync to be available.

Based on the described setup, the supported options are:

• Use Outlook for Android for email, calendar, and contacts management.
• If calendar/contacts must sync to the phone’s native apps, use an account type that supports Exchange ActiveSync rather than IMAP/POP.
• If the mailbox provider only offers IMAP/POP for that account, calendar and contacts sync will not work through Outlook for that account.

If this used to work with the phone’s native Calendar and Contacts apps and now only Google/Samsung accounts appear, that indicates the Outlook account is no longer exposed to Android as a sync source. The documented self-service checks are the Outlook app permissions, Sync Contacts, calendar selection, Reset Account, and re-adding the account. If the account remains IMAP, there is no supported way to make calendar and contacts sync through that account.

For a work or school Microsoft 365/Exchange account, contact the Microsoft 365 admin or technical support. For Outlook app or Outlook.com account issues, use Microsoft support or the Contact Support option in Outlook mobile.

References:

• Can't sync calendar and contacts with my phone or tablet | Microsoft Support
• Troubleshoot Outlook mobile issues | Microsoft Support
• syncing outlook with android email - Microsoft Q&A how do i sync windows 365 outlook with google email on my laptop and android phone?
• Mail in Outlook not working proerly - Microsoft Q&A