Please try the below:
1. Ensure the SIM card's GPRS Traffic is on.
2. Check if the network signal in your area is working properly.
3. Use a different SIM card to see if can download MMS and rule out a defective SIM card.
4. If the MMS still cannot be downloaded after above steps, try restoring to factory settings after backing up important data.
If the issue persists, please contact our Customer Support for further assistance.