Step 1: Log in to Office 365 and go to the admin centre page

Click on the grid on the top left corner and choose Admin.

Step 2: On the left menu, go to Azure Active Directory

On the left menu, click on Show all
Scroll down a bit and click on Azure Active Directory

You land on a new page, click on Azure Active Directory on the left menu
A new menu appears, scroll down and click on Properties


Step 3: Disable security defaults

On the bottom, click on Manage Security Defaults
Select No within the right-hand slider window
Save



Step 4: Go to the email settings of the email account you want to connect

On the left menu, click on Users > Active Users. Choose the account you want to connect by clicking on it, you should see a flyout coming from the right, click on Mail > Manage Email Apps


Step 5: Make sure IMAP is activated

On the new flyout on the right, make sure IMAP is checked like on the screenshot below. Then click on Save Changes. You should see a confirmation message highlighted in green telling you the information has been updated.


NOTE: If you have 2-Factor Authentication (2FA) enabled or a Single Sign-On enabled, you need to create an App Password by following the instructions below.


https://support.microsoft.com/en-us/account-billing/using-app-passwords-with-apps-that-don-t-support-two-step-verification-5896ed9b-4263-e681-128a-a6f2979a7944


OR


https://docs.microsoft.com/en-us/azure/active-directory/user-help/multi-factor-authentication-end-user-app-passwords


Step 6: Provide the details to MassMailer

Provide the following details to MassMailer in order to set up the MassMailer Inboxing Service.


First Name, Last Name, Email Address, Password