If you see an error next to your Microsoft mailbox, you likely haven't enabled SMTP.
Understanding SMTP
SMTP (Simple Mail Transfer Protocol) is the standard protocol for sending emails. To send emails from your Microsoft mailbox using an external application or device, you'll need to enable SMTP authentication.
Enabling SMTP for your Microsoft mailbox
Disclaimer: The steps outlined below assume you have administrative privileges for your Microsoft 365 environment. If you do not, you'll need to contact your IT administrator for assistance.
Step-by-Step Process
Log into your Microsoft Admin center.
Open Users -> Active Users.
Select the mailbox for which you want to enable SMTP.
In the side window, click on the Mail tab, and then on Manage email apps.
Check the Authenticated SMTP box and click on Save Changes.
Ensure that the IMAP box is checked too.
Now add the mailbox in GetReplies.
In case it continues to give an error, then wait for some time. It takes some time to reflect.
Image guide
Enable SMTP for Microsoft mailbox: Navigation
Enable SMTP for Microsoft mailbox: SMTP and IMAP checkboxes
Further assistance
If you continue to have an issue, contact us through our chat support. We'll do our best to fix your mailbox issue.