Hi @Siebe Sietsma ,
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According to my research, sometimes, contacts might be hidden or not synced properly. Log in to your Outlook account on a web browser and check if your contacts are still there. If your contacts are here, the issue is likely a syncing problem on your iPhone. Try:
Verify Outlook Contacts Sync is Enabled
Go to Settings > Mail > Accounts > [Your Outlook Account].
Ensure Contacts is toggled ON (not just Mail). If it was off, turn it on and wait a few minutes for syncing. Restart your iPhone afterward to force a refresh. If it is already on, try turning it off and then back on to force a re-sync.
Check Hidden Contact Groups
Open the Contacts app.
Tap List (top-left corner).
Ensure all groups (especially "Outlook" and "All iCloud") are selected. If "Outlook" is unchecked, select it and your contacts may reappear.
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