"SIM card rejected"

[inquisitor]

If you have locked the SIM by incorrectly entering the PUK ten times, it's useless. Then it can't be reset OTA, since your phone will not even try to register to any network.

The code you're being asked after swapping SIMs is the security code of your phone, which should be 12345 for Nokias by default.

But again: When you switch on the your phone with the Poste SIM inside, which codes are you asked?
Can you access the menu or does the message "SIM card rejected" appear continiously?

[wco81]

I know I didn't enter it 10 times.

Had a similar problem with an Aldi SIM purchased in Berlin in 2006 too.

It kept asking me for the PUK and I hadn't wrote it down.

That's the thing which is frustrating about the prepaid SIMs. When I take them out after returning to the US and then try to use them again after several months, they keep prompting for the PUK the first time I power them up.

I can take my US T-Mobile prepaid SIM in and out and it never asks for the PUK or any PIN.

I was suppose to have 12 months of credits left and now, looks like I wasted another SIM for nothing.

[inquisitor]

No SIM will require you to enter the PUK unless the PIN was entered incorrectly for three times. Since you totally ignore my explanations and questions you seem to have a weakness in reading carefully and understanding, which I fear also caused your handling error resulting in blocked SIMs.