To do this HawkOpen needs access to your mailbox. Gmail connects with Google’s full mail permission, the one Google requires for IMAP and SMTP; Outlook connects with IMAP and SMTP permissions; other mailboxes with their own IMAP and SMTP login.
The privacy page lists the data HawkOpen may handle depending on the features you use, such as message and recipient metadata, open and click observations, replies and documents you submit. The account privacy tools let the account owner export or delete account data.