Sending data to server using GPRS Answered

I am trying to send the data using gprs sim 800a,i am getting network error,before executing the AT+SAPBR=1,1 Signal strength will be good but as soon as AT+SAPBR=1,1 is executed led starts blinking continuously and returns response code 601.can anyone please help me how to resolve this issue? here is the AT commands used and the responses i got

AT

OK

AT+CGATT=1

OK

AT+SAPBR=3,1,"Contype","GPRS"

OK

AT+SAPBR=3,1,"APN","airtelgprs.com"

OK

AT+SAPBR=1,1

OK

AT+HTTPINIT

OK

AT+HTTPPARA="CID",1

OK

AT+HTTPPARA="URL","URL:PORT"

OK

AT+HTTPPARA="CONTENT","application/json"

OK

AT+HTTPPARA="USERDATA","KEY1:VAL1, KEY2:VAL2,..."

OK

AT+HTTPDATA=40,80000

DOWNLOAD

{\r\n "m2m:cin" :{\\r\n "con" : "FIRE"}\r\n }

ok

AT+HTTPACTION=1

ok

+HTTPACTION:1,601,0