Leads are objects in Salesforce that are similar to Contacts - there are fields like phone number. In Salesforce, you can convert a Lead to a Contact or Account, but Front only syncs Contacts and Accounts from SFDC at the moment
Allow user to disable email notifications for failed Hubspot / Salesforce contact sync
While there has been a sync error, for us it's not the end of the world. Therefore if there are some sync errors we really don't need the daily notification email warning us.