Are you including the client_id in your logout request? For example:
https://YOUR_DOMAIN/v2/logout?returnTo=http%3A%2F%2Flocalhost%3A85&client_id=YOUR_CLIENT_ID
Are you including the client_id in your logout request? For example:
https://YOUR_DOMAIN/v2/logout?returnTo=http%3A%2F%2Flocalhost%3A85&client_id=YOUR_CLIENT_ID