Hi PM and JD,
Welcome to Microsoft Q&A forum.
To help narrow down the issue with Contact lists/Contact groups in New Outlook, please help check the following:
- Open New Outlook > select People (the People icon on the navigation bar) and let us know whether your Contact list/Contact group appears there.
- If Contacts/Contact lists are visible in People, please try creating a new Contact List directly in People to test syncing: New Outlook > People > select a contact > Add to list > New contact list (name it) > Save.
- After that, please confirm whether the newly created contact list appears in People and/or Outlook on the web.
Once you have the results, please update us so we can assist further.
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