After new update dual Sim 4g is not working properly. One of the Sim network keeps changing from 4g to 2g (Airtel). It works fine with one Sim turned off but as soon soon as I turn on both the Sim in 4G mode one of the them start converting to 2G mode automatically even. I am using Samsung m21. If anyone else facing the same problem in M21 please raise a complaint to Samsung and support this post so that Samsung can provide some update.
Dear Samsung Member,
Greetings from Samsung Customer Support!
To resolve your device network issue please visit this link: https://www.samsung.com/in/support/mobile-devices/samsung-mobile-network-issues/#:~:text=1%20Check%2....
For further assistance, register your concern in Samsung Members Application (Open Samsung Members Application > Get help > Send Feedback > Error report/Ask questions).
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Samsung Customer Support