I have problem with my phone network Samsung Gio S5660. How can I fix it?

[AC Question]

I have problem with my phone network samsung gio s5660.

I have samsung gio s5660.after root I flash a custom rom.now everything is fine but when someone calls me it show my number busy to the caller , i install another custom rom but still i facing this problem . how I solve this problem plz help me...