Please input the sending domain/subdomain you configured in your Brevo (formerly Sendinblue) dashboard. More information can be found in our <a href="{bbackup_94402fb9ba80f392e0976ece85f92b2b876bfcaed8d83250cc06083f7139c7d9}s" target="_blank" rel="noopener noreferrer">Brevo documentation</a>.