Why is it not possible to sendt e-mail to the organisation users directly from AGOL or Portal?
AGOL does not have a built in SMTP server is one reason.
Creating a way of notifying users in the organization is something that we are considering. Currently, there are some external scripts that enable this capability using something like this script: A simple e-mail notification system for Survey123 for ArcGIS v2
I'd suggest supporting and following this idea on Introduce email notifications for ArcGIS.com group owners & members. or submit a new idea.
Could you provide some additional details about the circumstances in which you would want to email your organization and how often?
Notify of new content?
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