Thanks for reaching out!
One thing that could be of much help to us is if you can share the GPRS module that you are using. If we had this information we would be able to look for more specific causes for this behavior.
Nevertheless, I read online that something that could be happening is that the GPRS module is already connected to the ISP when you try to connect it. If this was the case, you could try resetting the module before entering the AT+SAPBR commands.
Also, something else that you can try is setting the APN settings with the AT+CSTT= command. You can find details about the AT+CSTT command in http://m2msupport.net/m2msupport/atcstt-satrt-task-and-set-apn-username-and-password/.
I hope this information helps you,
From what I read in http://linksprite.com/wiki/index.php5?title=ATWIN_Quad-band_GPRS/GSM_Shield_for_Arduino, I understand that there is a library for this shield. Why aren't you using it? Is it incompatible with Galileo's x86 architecture? Or, is there any other reason?
In case it is compatible with Galileo, I suggest you to try using it and to check the link I shared above, it includes an example which you might find helpful.
Also, I wanted to ask you if you tried my other suggestion. I mentioned that there were issues with certain modules where they would throw error messages when they were connected to the network before the connection commands arrive to them and some people have reported to fix this behavior by resetting the module before entering the commands. Did this help you?
Let me know.
Sorry for the late reply.
Sir you had mentioned an inbuilt library for the linksprite gprs module, if you are talking about the softwareserial library, then Sir galileo does not support softwareserial library. Is there any other library you were talking about?
As you had asked me to reset the module and I did that also, I had reset the board as well as the galileo, but it did not work.
While indeed SoftwareSerial is not supported by Galileo, if you have a Galileo Gen 2, there is a workaround that will make it work on pins 2 and 3. In case you are interested on this workaround, you can find it in https://github.com/MakersTeam/Galileo/tree/master/Arduino-Examples/SoftwareSerial.
While reading http://linksprite.com/wiki/index.php5?title=ATWIN_Quad-band_GPRS/GSM_Shield_for_Arduino I found something very important. It is stated that the shield must be powered by a wall adapter with 9V, 1A. And I got confirmation that it will not work if powered in a different way in http://forum.linksprite.com/index.php?/topic/2466-pin-connections-for-atwin-quad-band-gprsgsm-shield/. How are you powering your shield? Are you trying to power it through the board? If so, this will not work, you'll have to use a different power supply for this shield. In case you haven't, please try this and let us know how it goes.