unable to make calls

[SarathBK]

keep getting "Your Device unable to make calls or connect to mobile network" on my M31S.

[Techilicious]

take and place sim again

[Anikroyale]

Visit a service center. I had this exact same issue a few months back on my M31s. They changed the motherboard and its working fine.

[ashukr9867]

same problem happened with my m31

[Ehsank]

once go to settings >general Management >reset >reset network