Organizing and accessing contact information in Outlook.com
Hi, James Collett
Thank you for your update. I'd like to let you know that the "Outlook Web" is still considered a different version and it may have some features that are not working properly, so I advise you use Outlook classic or Outlook new that had installed in your computer as an application and see if you still had the same problem. No matter what version of Outlook are you using, your contact list will be synchronized.
Also, If you have noticed that this contact feature was working before. You can try again later as there may be something wrong in network temporarily. I have already submit this issue to Microsoft support team and thank your for your cooperation.
You can also report this issue in Outlook web
I hope the issue you have encountered can be fixed as soon as possible and feel free to let me know if you have any update.