s23 ultra

[dxboy]

My phone prompt msg insert sim card again and again why i dint no as their is sim inserted 

[GreaterGalaxyUK]

Take the sim out, restart the phone and enter it. Try it in another phone. It could be a SIM issue as opposed to the phone. Contact the network provider. They can send a new sim out to you.

[AndrewL]

@dxboy: Further to the above, I would also encourage you to try inserting your SIM into the second SIM slot, to see if this helps.