This is not a product issue. OUTLOOK SMTP email server will not allow you to send emails from the MAIL FROM addresses you specify if it's not the same as authenticated email(SMTP Username)
If the application was configured with an Office365 account, It was connecting to the SMTP-mail.office365.com. It can send email messages using the configured SMTP email address (support@agile-labs.com) only, which means the SMTP configuration email and Axpert User Email should be the same.
If you want to send emails using another email address as the MAIL FROM address (e.g. Admin@agile-labs.com), those email accounts must allow the Login Name to send messages on its behalf.
This can be done in the MS OUTLOOK admin panel by setting Relay/delegation rules. This may need to be checked by the corresponding IT admin team.
Kindly refer to the below links for a better understanding,
https://stackoverflow.com/questions/54784431/unable-to-send-smtp-mails-using-office365-settings
