For Drupal 8/9, since CiviCRM 5.47, we can use the new /civicrm/ajax/rest url [CiviCRM REST URL](https://lab.civicrm.org/extensions/outlook365/-/blob/master/docs/GettingStarted.md#civicrm-rest-url) Can be updated to mention For **Drupal 8/9** sites with CiviCRM, the CiviCRM REST URL is (typically), https://your.domain.name/civicrm/ajax/rest [CiviCRM Permissions](https://lab.civicrm.org/extensions/outlook365/-/blob/master/docs/GettingStarted.md#civicrm-permissions) Should be updated For **Drupal**, go to People, Permissions and enable the **Access Outlook 365 pages** permission to **Anonymous User** and **Authenticated User**. Otherwise, we get "Access Denied" page instead of TaskPane after login to edit a contact from the Outlook browser