Before you can use an email address as a "from address" in marketing emails, you must verify that the email address belongs to you or your company, or that you have access to it.
Please note: as of January 30, 2019, Marketing Hub Basic, Professional and Enterprise accounts will be required to have all from addresses verified for all new and existing emails. Users in these accounts can verify email addresses in advance of this date to prepare for this requirement.
If you have a connected email sending domain, all existing and new from addresses at that domain are automatically verified. For example, if you have a connected email sending domain for domain.com, new and existing email address such as john@domain.com or info@domain.com are automatically verified. The email addresses of all active and confirmed users in an account are also automatically verified.
To verify an email address that doesn't match a connected email sending domain or an existing user: