If it doesn't work still, talk to each one personally and figure out where the problem lies. Is there some discord or misunderstandings that needs to be addressed . Are there problems you are not aware of, get individuals talk about them.

Ask them what they think about their team members, their strengths and weaknesses .

You will get a hang of who thinks what. That should help you take a call for future action.

Try figuring out if you have the right people in your team. Putting those people together who can't see eye-to-eye , will lead you nowhere.

Team is made up of individuals aligned to a common goal. If people are just not interested, you may as well think of better options.