Error - '5.2.0 STOREDRV.Submission.Exception:SendAsDeniedException' when trying to email an alert

This is an error directly from your SMTP server or Office 365 and as such is not supported by Access.
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The most common cause is that the account which is being used to send the emails, does not have permission to “Send email on behalf of another user” but is being used on the Task to look as though its coming from a different email address.