To enable Multi-Factor Authentication on new or existing Cloud App Security Service Accounts:

1. Log in to the Office 365 Admin Center.
2. Select the Users > Active Users tab.
3. Select “Cloud App Security Service Account for SharePoint” from the Active Users list.

   

4. Click Manage Contact Information to update the service account with a mobile phone number for authentication purposes.

   

5. Reset the password using the "Let Me Create the Password" option.

   

6. Click Manage Multi-Factor Authentication for the User account.

   

   This will redirect to the multi-factor authentication page.

7. Select the User account and click enable multi-factor auth.

   

8. Log in to My Account using the service account name and the new password created in Step 5, and complete the multi-factor login using the code sent to the mobile phone number added in Step 4.
9. Once the login has been verified in My Account, navigate to Security & Privacy > Additional security verification > Create and manage App Passwords.

   

   

10. Click Create and name the new password "Cloud App Security".

    

    

    The name of the app password and the password will be shown on screen.

11. Copy the password by clicking copy password to clipboard.

    

12. Log in to Cloud App Security and navigate to Administration > Service Account.
13. On the SharePoint service account, select "Change Password" then paste the new app password and save it.