Outlook Calendar No Connection

Outlook Calendar No Connection. User can see some user calendars but sometimes when user tries to see a user calendar they receive ‘no connection’ message. Sync issues folder has errors, but they're.

One user cant access shared calendars in availability only rights has a no connection error, but if the rights is elevated to reviewer or editor only then the calendars are accessible and the error is not there. Kindly check and implement the following steps to resolve the issue.