Forum Discussion
Restrict access for AD to AD Azure synced user to Office 365
Block a former employee's access to Office 365 data
IMPORTANT: Blocking an account can take up to 24 hours to take effect. If you need to immediately prevent a user's sign-in access, you should https://support.office.com/en-us/article/reset-their-password-7a5d073b-7fae-4aa5-8f96-9ecd041aba9c and then initiate a one-time event that will sign them out of Office 365 sessions across all devices. See https://support.office.com/en-us/article/remove-a-former-employee-from-office-365-44d96212-4d90-4027-9aa9-a95eddb367d1#bkmk_now
To block a user from signing in and accessing Office 365 data:
Go to the https://portal.office.com/adminportal/home.
In the Office 365 admin center, select Users.
Select the employee that you want to block, and then choose Edit next to Sign-in status in the user pane.
On the Sign-in status pane, choose Sign-in blocked and then Save.
Note : You can also block a former employee's access to email (Exchange Online)