Hi @ThLm,
Welcome to the community. I am sorry to hear you are having trouble with your XZ.
The first thing I would like you to do is go to Settings > More > Internet Settings, and accept this. This will make sure your phone has downloaded the MMS settings from your network provider.
Once you have done this, please try to send an SMS and an MMS to your own phone number, and let us know if this has been sent and received successfully.
