Guide includes settings for several popular devices including iphone, ipad, android & blackberry etc.
If you find the APN/Data settings are correct and still unable to connect Check the signal in your area to check for any faults with the network in your area. You can do so by following this link https://giffgaff.com/coverage-and-service
PLEASE NOTE: the checker only gets updated once an hour so if your problem has just started, or you’re not sure how long it’s been happening, if it says all is good, keep trying for a while to see if it gets an update.
Check in your phone settings to see if your APN is set to giffgaff or 02. If it's 02 you need to CREATE a new APN inputting the giffgaff settings and remember to save them do not try to overwrite the 02 settings you must CREATE a new one and when created, SAVE it. Once it's done giffgaff will show up as a selection in your APN list, just tap the dot to the side it will turn green and your done. Reboot the phone and BINGO. it works.