Problem:

When receiving an SMS or downloading an MMS on the secondary SIM card, the data service for the primary SIM card is temporary disabled. It will return to normal only after the message is received or the download is complete.

Cause:

This is due to the fact that your smartphone is dual SIM dual standby*. When messages are sent to the secondary SIM card, the device gives priority to receiving those messages. This will interfere with the Internet connection of the primary SIM card, which cannot access the Internet. It is normal and does not indicate an issue with your device.

Suggestion:

We recommend you to open Messages, go to > Settings> Advanced and deactivate Auto-download MMS. Next time the secondary SIM card receives an MMS, you will get a notification and you can choose to download the MMS when the primary SIM card is not accessing the Internet.

For some phone models with dual-VoLTE enabled, the primary SIM card can access the Internet when the secondary SIM card is making calls or receives messages.