outlook.com contacts and calendar corrupt. stale contacts, which I cannot delete. Calendar not syncing to iPhone

Henk en Lucienne Naber 0 Reputation points
2026-11-01T18:30:41.7133333+00:00

On 2 of 4 Apple devices the calendar does not sync. Yellow triangle with exclamation and message 'Cannot update calendars' (in Dutch). I don;t see any items in my agenda.

Also some Contacts cannot be deleted. They are in a folder named 'Agent Registry Contacts'. And doubled/trippled in the contacts list.

I already removed the account completely, restarted the iPhone. But no succes.

Outlook | Web | Outlook.com | Calendar
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  1. Chloe-V 15,075 Reputation points Microsoft External Staff Moderator
    2026-11-02T05:01:48.6833333+00:00

    Hi @Henk en Lucienne Naber

    I understand that the Outlook.com calendar is not syncing on two of your Apple devices, and that some duplicated contacts in the “Agent Registry Contacts” folder cannot be deleted.

    To help narrow down where the issue originates, please sign in to Outlook.com in a web browser and check the following:

    • Do your calendar events appear correctly under Calendar?
    • Under People, do you also see the “Agent Registry Contacts” folder and the duplicated contacts?
    • Are you able to delete one of the affected contacts directly from Outlook.com?

    If the calendar and contacts appear correctly on the web, the issue is likely related to the account synchronization on the affected devices. In that case, please go to Settings > Apps > Calendar > Calendar Accounts on each affected iPhone, select the Outlook.com account, and confirm that Calendars and Contacts are enabled. Then open the Calendar app, select Calendars, and swipe down to refresh.

    Please also let us know the iOS versions installed on the affected and working devices, and whether the Outlook.com account was added using the Outlook.com option or another account type.

    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread. 

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