The error message you're encountering indicates that you are experiencing authorization issues while trying to synchronize a SharePoint calendar with your Outlook desktop. To resolve this problem, you can follow these steps:
Verify your permissions: Ensure that you have the necessary permissions to access and synchronize the SharePoint calendar. Check with your SharePoint site administrator or IT department to confirm that you have the appropriate rights.
Check SharePoint calendar permissions: Make sure that the SharePoint calendar itself has the correct permissions configured. Verify that you have at least "Read" access to the calendar. The site administrator or owner can check and adjust the permissions settings for the calendar.
Clear credential cache: Clearing the credential cache on your computer can sometimes resolve authentication issues. To do this, follow these steps:
Close Outlook and any Office applications.
Press the "Windows Key + R" to open the Run dialog box.
Type "control keymgr.dll" and press Enter.
In the Credential Manager window, under "Windows Credentials," locate any entries related to SharePoint or Office 365.
Select each entry related to SharePoint or Office 365 and click "Remove" or "Remove from vault."
Restart your computer and try synchronizing the SharePoint calendar with Outlook again.
Repair Office installation: If the issue persists, you can try repairing your Office installation to fix any potential configuration problems. To repair Office, follow these steps:
Close all Office applications.
Go to the Control Panel on your computer.
Click on "Programs" or "Programs and Features."
Locate Microsoft Office in the list of installed programs and select it.
Click on "Change" or "Modify."
In the Office Installer window, choose the "Repair" option and follow the on-screen instructions.
Once the repair process is complete, restart your computer and try synchronizing the SharePoint calendar again.
