To avoid sending out spams make sure that all the contacts in your import list has asked to receive emails from you or have close relationship with your organization.When importing your data through CSV or Excel, select “Accounts and Contacts” or “Contacts” as the destination, a checkbox will show up with the following message:
Please verify that these contacts have given you their
permission to email them. We do not allow rented or
purchased lists. These contacts must have either asked
to receive emails from you or have close relationship
with your organization.
Until the checkbox is checked, the “Select” button will not be active and the you will not be able to move to the next step.