If you are trying to send via Gmail then it won't accept your usual username and password. Instead, try setting up an App Password from your Gmail account and using that instead from your Mendix app.
https://support.google.com/accounts/answer/185833
I hope this helps.
Hey Robert,
Thanks for replying. I've tried for both microsoft and google account neither of them working.
I've tried configuring in 2 ways.
1) Through Basic credentials -> The verification itself got failed. I've attached the image for reference above
2) Through OAuth2 Configuration (microsoft account) -> The verification is completed successfully but the when i tried to initiate mail, its not working.
I've entered Client ID, Tenet ID, Client Secret with Microsoft Graph - SMTP.send and Mail.send with admin consent enabled.
Attaching the snap below for reference.
Any help is appreciated. Thanks in advance.