Hello Stephen Fryer1,
Welcome to the Microsoft Community.
I understand that you receive an error message when clicking on a group.
After testing, I encountered the same issue when clicking on a group.
This seems to be a widespread problem rather than something only you are experiencing. It might require waiting for Outlook.com to fix it.
You can submit your feedback through Help > Feedback at the top of Outlook Web.
You can also follow these steps to contact Outlook.com's online support directly to report this issue.
- At the top of Outlook Web, click Help > Help.
- Enter your issue.
- Under "Still need help?", select Yes.
- After completing the login, choose Chat with a support agent in your web browser. TIPS: Please contact us during local working hours on weekdays. CHAT does not work 24 hours a day.
Thank you very much for your feedback and contribution.
Best Regards,
Zachary.W - MSFT | Microsoft Community Support Specialist