Edition: Professional, Business, Enterprise
User-level: Assistant Administrator, System Administrator
If you're trying to add a staff member or contact to the project contacts list, and you can't choose a specific role for them, it's likely because that role isn't available for that type of contact. To fix this, you will need to make sure the role you want to assign is set up for that type of contact.
Settings > Contact List > Roles.
Select the edit pencil to the right of the role you would like to apply to a contact
Ensure the contact role or staff role checkbox is selected
Select the check button to the right