I got a new moto z2 from ebay I try to use my old sim card and it said invalid simcard so I got a new sim card from at&t and they activate the sim card and the phone but still sayng invalid sim card

SOURCE: problem regarding mobile sim card chang

Your phone is asking for a code because it is locked to only work with one phone company. If your new sim is from a different company, you can request the unlock code from your old company, they may or may not give it to you (tmobile usually does, ATT/Cingular usually doesn't). The other option is to use a unlocking service, you can find plenty on ebay. If you didn't change phone companies, your new sim card is most likely bad, have your phone company send you another one.

SOURCE: CAN NOT FIND SIM CARD ON MY ALLTEL HUE

Alltel doesen't use SIM cards. You bought a phone for use on a GSM network, which in the US is T-Mobile and AT&T.

You would have to buy another phone that is branded for alltel and call customer service to switch phones.

SOURCE: invalid sim message on i68 phone

i've got the same problem. Both sim slots work, but doesn't seem to accept vodafone and O2 sim. Seller in China states 'never had this problem before' Looking at the responses here I start to doubt that. Any solutions?

SOURCE: i bought an at&t lg neon go phone. i already

Hi there i think your new phone lock, you should buy a New Universal Cell Phone Turbo Sim Card Unlock GSM Card from ebay, it only cost $1.00 and can be use to unlock any cell phone its interesting i think you should try it.

SOURCE: how to fix an invalid sim card

try a different sim card if that doesent work then it might be the phone