Currently Being ModeratedJan 2, 2014 6:26 AM (in response to aramjc777)
Contact AT&T regarding your wireless connection issues.
Currently Being ModeratedJan 2, 2014 6:43 AM (in response to TJBUSMC1973)
It is not AT&T issue it is phone issue because i have tried the same sim card on my other iphone 5s and working fine.
Currently Being ModeratedJan 2, 2014 7:18 AM (in response to aramjc777)
That would have been helpful information to provide in the beginning.
Try the following:
Settings > General > Reset > Reset Network Settings.
Remove and reinstall the SIM.
Basic troubleshooting from the User's Guide is reset, restart, restore (first from backup then as new). Try each of these in order until the issue is resolved.
If the issue continues, take the device to Apple for evaluation.