There are three requirements for the user to appear in the owner, assignee and follower dropdowns in tasks.
- The user must be a person who can log in (not a contact) and their status must be set to active.
- They are not an executive level user. Executive users cannot be owners, assignees or followers of tasks. This is by design and they live one step outside of the task flow where they are more of a reviewer and never see assignees.
- They must have access to the project that the specific task belongs to. Check the project’s profile page under the team section to determine if they have access.