SIM Not Valid: The SIM card inserted in this iPhone does not appear to be supported.
I initially had a contract with AT&T for a 'post-paid' plan. I terminated the contract, paid the ETF (Early Termination Fee) and ported the number over to Cricket Wireless. The 'port' worked fine for about 4 months, which is to say that the (Cricket) SIM card worked when inserted into the iPhone 4S.
I recently switched over to Ting, and activated the SIM card. However, when I insert the Ting SIM card into the iPhone, I get this frustrating error message:
SIM Not Valid
The SIM card inserted in this iPhone does not appear to be supported.
The SIM card that you currently have installed in this iPhone is from a carrier that is not supported under the activation policy that is currently assigned by the activation server. This is not a hardware issue with the iPhone. Please insert another SIM card from a supported carrier or request that this iPhone be unlocked by your carrier. Please contact Apple for more information.
I verified that the Ting SIM card works / is activated, by inserting it into another (Android) phone that I have.
I have received (3) unlock emails from AT&T asking that the phone be backed up, erased and then restored. However, after doing so about 5-7 times in a variety of ways, I have had no success. AT&T customer service / support has not been responsive, helpful or proactive in this case and I am at my wits end.
Any helpful feedback or suggestions on how to resolve this issue would be much appreciated!