My reply from MG regarding the same issue -
Dear Customer,
Our analysis indicates an issue with your vehicle's telematics box (TBOX), which is preventing the MG iSMART App from connecting to your vehicle.
We recommend visiting your local MG dealer for a diagnosis. Please provide them with the following information:
1. Prioritize a vehicle diagnosis focusing on the TBOX.
2. Create an SNW ticket.
3. If an error is found with the TBOX, proceed with a replacement using SIPS, but do not replace the hardware.
Thank you.
Best regards,
iSMART Service Team