Sim868 httppost 603 error

Hi
I’m using sim868 alongside with airtel india sim card.
When I try a http post method occasionally I receive httpaction: 1,603,0 which according to the documentation says it is a dns error.
Set of commands sent

  1. For gprs connection
    At+sapbr=3,1,“contype”,“gprs”
    At+sapbr=3,1,“apn”,“airtelgprscom” //assume a dot after gprs as not able to create topic with one :wink:
    At+sapbr=1,1// for bearer connection
    At+sapbr=2,1// for confirmation by checking the ip

  2. Http posting
    At+httpinit
    At+httpparam=“cid”,1
    At+httpparam=“url”,"$url"
    At+httpdata=$data_length,10000
    At+httpaction=1
    At+httpterm

I’m not finding the problem as I’m sending the commands according to the sim application note.

Any suggestions welcome.
Thanks in advance