Using Classic Outlook on Windows for personal email, calendar, and contact management
Dear Sharon
Good day!
Thank you for posting to Microsoft Community. We are glad to assist!
Based on your description, I do apologize that you are experiencing sharing calendar request not working.
May I know whether you have the same issue in Outlook on the web? You may need have a try to resent a request in Outlook on the web, refer to Share your calendar in Outlook on the web - Microsoft Support.
May I know what version of Outlook you are using What version of Outlook do I have? - Microsoft Support ? Is it New Outlook or Classic Outlook?
May I double confirm whether all the users has enabled the "Can view all details" in Calendar permissions, refer to Share an Outlook calendar with other people - Microsoft Support.
If the issue still persists, please feel free to let me know. I will continue to assist you. I look forward to your response.
Please note that our initial response may not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution.
Thanks for your precious time and your understanding would be highly appreciated. Have a nice day!
Best regards,
Allen | Community Moderator