Forum Discussion
You are not authorized to send mail on behalf of the specified sending account.
IMJMel The ability to send on behalf of another user is set at the O365 User Admin level. You will need to get your admin to set it up - typically, and understandably, they will be reluctant to do this!
An more complicated alternative is to send the email as a Dynamics email from Power Automate.
https://www.crmsoftwareblog.com/2020/01/send-dynamics-365-emails-from-power-automate/
Note - worth checking if your scenario will allow you to use a traditional workflow - sending Dynamics email from these is a lot easier than from Power Automate.
Then you can use the User Settings Utility in XRM Toolbox to change a users settings to allow you to send Dynamics Email on their behalf (Dynamics email will need to be set up in the environment - if your organization has more than one environment, be very careful here as currently Dynamics email can only run in one environment in an O365 Tenant.