A family of Microsoft on-premises document management and storage systems.
To narrow this issue, I have something to confirm with you. What’s the smart host configured in your SMTP Server? Did you check the Attempt direct delivery box under smart host? The system may attempt to deliver the email directly first before sending to the Smart host.
Did you set the “From address” on web application level through: Web Applications Management page, select a web application, and then in the General Settings group on the ribbon, click Outgoing E-mail?
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