If you’ve been authorised to access the messages in another person’s Message Box, you can do so by logging in to your own MijnOverheid account.
You can read, move, delete or forward only the messages you’re authorised to access. On the DigiD authorisation website you’ll find a list of the organisations for which authorisation is possible (information in Dutch).
It is not possible to access another person’s messages using the Message Box app.
If you have any questions, please do not hesitate to contact us.