Sim800L has no signal at all and cannot connect to network

GSM/GPRS Modules
#1

Hi, I have a Sim800L and want to send data to a server. Previously, I managed to connect to the network. After I have discovered the power supply problem (due to my module keep resetting itself) and changed my circuit to supply the Sim800L with 5V and 2A, I failed to connect to any network.
I have checked AT+CBC command and get >80% in voltage. but I am still unable to attach to GPRS. When I perform AT+CGATT=1 , it will always give me an ERROR and when AT+CREG?, I got 0,0 . But I do have signal as when I typed AT+CSQ, I got 13,0 and when AT+COPS=?, I am able to display the network operator.

May I know how to solve this problem please?

#2

What you need is 4V,2A on the module and not 5V, 2A. If you give 5V to it, it will shut down and enter Over-Voltage-Powerdown state.
P.S : You might as well have damaged it if 5V is directly connected to it.