My Activity History is not updating in Salesforce

When activity history doesn't update, make sure that you sent to a Mass Email list (it will say "Salesforce Mass Email" at the end of the list name) and that you checked the box to update leads and contacts on the email launch page. If the list says Salesforce Campaign, look for the campaign history to be updated instead, and if it says nothing, then the list was not generated within Salesforce, and doesn't have the necessary ids to update the account. The Activity history will not show any information on opens, links, bounces and unsubscribes.