[AC Question]

i have an android phone ( Blu ) and the sim card is not detecting at all can u help me out with this problem thank you

[SpookDroid]

SIM cards are tricky because it can be a number of reasons, so let me list out the ones I can think could help.
1) Make sure your phone is unlocked or you're using a SIM Card from the company you got the phone from. If it's carrier-locked, and you're using a SIM card from another company, it won't work.
2) Make sure the SIM Card actually works. Try it out onto another phone and see if it gets recognized and has service.
3) Make sure your SIM Card reader works. Try out the SIM Card from a phone you know it's working (remember the unlocked VS Carrier thing from #1, though) and insert it into your phone. Does it work there? If not, it's probably a hardware issue and then you should take the device for repair.

[siyo jemmott]

i tried all your options and still nothing is responding plz help me

[SpookDroid]

Wow, so the SIM card won't work on other phones? Dead SIM, get it replaced.
A working SIM card on another phone won't work on yours? Dead SIM Card tray; get your phone in for repairs.

Oh, and I forgot! If the phone you've got is not compatible with the radio network from your carrier, it won't work either (but even if this was the case, it should still be able to read the SIM Card, just not connect to any network).

[N4Newbie]

And make sure you power the phone off and them back on (that is, reboot) after inserting the card. Some phones (like Nexus 4 & 5) will not recognize the card otherwise.