My phone says insert correct sim card but i don't understand what is a correct sim card ? I already inserted different sim but it kept on telling insert correct sim card.

SOURCE: insert correct sim card

i you should try a software update, you can get this from www.sonyericsson.com/support. hope this helps

SOURCE: LG Prada - can't detect my SIM

Try the SIM in another phone. SIM cards go bad.
If it doesnt work in the other phone it will have to be replaced. I
THis can also be caused if you set up a PIN code and it was entered in wrong too many times and you did not use the right PUK code to unlock it. THis will permanently damage a SIM card.
f it does work in another phone then your phone is no longer able to read SIM cards. Check with the manufacturer for warranty info.

SOURCE: WHY DOES MY PHONE SAYS INSERT SIM

try taking SIM and battery out placing it back in an powering on.

If you try this and it still does not work you may need a new SIM card. Take it to a local dealer they should have a new SIM they will put your number on it and you will be back in business.

If the new SIM doesn't not work you will now know it is your Phone, which means time for a new one.

good luck

SOURCE: my i465 tells me to insert the sim card. why?

These phones are ****! Absolute ****! I have had my clutch for about 8 months now and have had it in to the nextel store at LEAST 4 times. I continue to get the "Insert Sim" message with no warnings what so ever. They have replaced my sim card like 3 or 4 times and they even replaced my phone once. I am currently having this issue now and plan to go back to nextel and give them a piece of my mind. These phones were also NOT built for texting. They are slow in receiving/sending messages and they lag behind while you are typing a message. I am very unhappy with the Clutch.

SOURCE: Sim card

if this is a new sim never been in the phone before it will require registering if is has been used before in the phone try another sim if that works the sim is faulty