Journey Builder Sales & Service Activities "Error: Your account does not have sufficient permissions to access this feature"

As an Admin, follow these steps to correct this issue:

1. Hover over your name on the top right of the Marketing Cloud and select "Setup"
2. Click the users in the left side panel.
3. Search for the user which is encountering the issue.
4. Click the username
5. View that the Salesforce.com Status is Not Integrated
6. Click on integrate and enter the appropriate Salesforce username for the user and click save.
7. Log out and login again. This should resolve the issue.

If you are still encountering the issue then review the following steps:

1. Navigate to Users
2. Search the user that is encountering the issue
3. Click the checkbox next to the username and click Manage Roles
4. Click Edit Permissions | Journey Builder | Sales And Service Cloud | "Create Events" and "Create Activities" should be Allowed. If denied, the user will not be able to configure these activities.