My sim slot is lock - Cell Phones

Remove back cover and remove battery and check sim is properly fixed in side sim slot or not. If sim is loose inside sim slot then put some paper packing make it properly fixed also remove sim and rub with cotten lock the golden part of the sim and insert again. Also check the sim in another mobile and if in that mobile sim also not recognized then there is issue with your sim card replace it.
here is how to sim unlock mobile http://mobile-cellphones.blogspot.com/2016/06/android-smartphone-sim-unlocking-details.html

try this link might help you out.... sim slot permanently locked how do unlock it Google Search

What is your mobile model?To insert simcard,the following conditions should be satisfied....
1)The mobile should be unlocked to accept the sim card
2)The mobile should have the sim slot (most CDMA phones do not have that provision)
3)The simcard size should be supported by mobile phone.
Now,if your mobile is locked with a particular network then you need to unlock it.For that you can either approach the respective network provider or third party unlocking services like Simpleunlocking.com or unBBlock.com (This is specifically for Blackberry phones) and unlock your mobile.Once your mobile is unlocked the sim slot will either be in the side or above or below the battery depending on your mobile model.If you search in Google you probably will get a more clear idea about where your sim slot is located.Once you find the sim slot remove the sim card and note down the position; replace it with the old sim card(it should support the phone sim size specification).

Hi i've samsung b210 mobile. my mobile sim track slot has been distroyed.so please help me in fixing sim track slot immediatly

you phone is not open line, that is why the simcard is not accepted. it is locked to a particular network.

maybe you didnt put it on the corect slot or you need to go to settings and it tells you what sim slot do you want to use for your sciphone i9+++ because i have one.

Hi Friend,
Kindly note down the below steps,

Unlock Method for SAMSUNG PROPEL A767. No Cables or Software Needed.

1. Turn mobile phone on with unaccepted sim BUT NOT FULLY INSERTED (only push it half way into sim slot).

2. Insert unaccepted sim to phone (push the sim fully into the sim slot).

3. Input *2767*3855# and phone will reboot and will be temporarily unlocked.

4. Input *7465625*638*00000000*00000000#

5. Input #7465625*638*00000000#

6. Input *#7465625# to check the locks....all locks should now be inactive as or similar to below:

network lock - inactive
subset lock - inactive
sp lock - inactive
cp lock - inactive
sim lock - inactive
activa lock - inactive
phone lock - inactive
auto network - inactive
auto subset lock - inactive
auto sp lock - inactive
auto cp lock - inactive
auto sim lock - inactive

Check and revert back

Regards,
Ayyasam

flip the sim card over and cutoff the other sim slot example"if chip is face down make it face up" if that doesnt work switch to other sim slot and repeat the steps above if that doesnt work you can go to this link for more help

http://www.freewebs.com/sciphone/index.htm

Here is two possibility either you used sim in wrong slot like you have nano sim and you used into micro sim slot or other different slot. or your mobile is sim locked and that is why it not accepting at&t sim. here is how to unlock at&t simcard.
As your att sim working fine with blackberry so sim is fine no issue with sim card. on which mobile you have tried this sim as you have not mentioned your other mobile it is same as blackberry or apple or samsung mobile.

If your phone has a dual sim card then the sim 1 card is the top slot and the bottom is the sim2
slot. Give it a try