When I preview the page and fillt he form and submit, email is not triggered.
Could anyone have suggestions on what I may be missing ?

Confirm the row is saved in Dataverse
Open make.powerapps.com → Tables → your table → Data. Submit the form and check if a new row appears.
Check the Flow run history
Go to Power Automate → My Flows → your flow → Run History.
Zero runs → trigger never fired
Runs present but failed → expand the run to read the error message
Verify the Flow trigger configuration
Open your flow and check the "When a row is added" trigger:
Table name — must exactly match the Dataverse table the form writes to
Environment — flow must be in the same environment as your Power Pages site
Check the connection credentials
Go to flow → Edit → Connections and confirm the Dataverse connection is valid (green tick). An expired or incorrect connection account silently prevents the trigger from firing.