It sounds as if people are not fulfilling their roles. My assumption is that part of being a team member is showing up for meetings. Do you have the option of replacing them on the team? If they’re not showing up for meetings, my guess is that they’re not doing any project work. If you can replace them I’d start there. If you are getting work done without them, you could ask if they want to be “Stakeholders” instead of team members. You may also ask them individually what’s keeping them from attending the meetings. You may institute team “calls” or change the time/venue if it’s not working for people. At a certain point, if they’re not showing up, they’re not really part of the team.