Why is "Send Email" button missing from Activity History related list?
|Knowledge Article Number||000176954|
|Description||Send an email button is missing from activity related list even after adding it to the page layout.
|Resolution||If the Access to Send Email level in your organization is set to No Access or System Email Only, then the Send Email button will not be visible from the Activity History related lists.
To change this setting:
Go to Your Name | Setup | Administration Setup | Email Administration | Deliverability
On Access to Send Email section, make sure that the access level is "All Email"
After changing this setting the Send Email button should now be available from the Activity History related list.