Microsoft Outlook

1. I get this issue when I try setting up YaySMTP with my Outlook Microsoft mailer.

Mailer: Outlook Microsoft
[404]: The mailbox is either inactive, soft-deleted, or is hosted on-premise.

This issue was caused by using an Azure AD user with no valid M365 license assigned. You are getting this error because no Exchange Online mailbox is available to use for the Azure ad user who does not have a valid M365 license. This will only be available/created for users with a valid M365 license.

1. I connect with the Microsoft Outlook SMTP server to YaySMTP and noticed this error message as below:

Your Client ID or Client Secret are not correct.

You should double-check whether you copied and pasted the API key and Client ID correctly. Copy the Application (client) ID (as in the image below) and paste it into the Client ID field of YaySMTP settings on your website carefully.

After creating a client secret, you will see a Client secrets item. Copy its value and paste it into the API Key field.