What is code puk

If you add a new Fizz’s SIM to your phone and the phone ask for a PUK this means that your phone is SIM locked the provider from which you get the phone must give you the unlock code for free.

This is the long explanation


The SIM Card won't require an unlock code or a PIN code the very first time you insert it in your phone.

The PUK code is necessary only if you had previously entered an incorrect PIN code for 3 times, which I don't think that it applies to your case.

When you get a message on your phone screen asking you for a SIM unlock code, it means that your phone is locked with another provider or seller. Therefore, in this case, you should contact the provider or the seller and ask them for an unlock code.

Also, in order to be unlocked successfully, your phone must not be declared lost or stolen.
If you buy a phone from a private source, verify that it’s not on the National Stolen Device Blacklist by entering the phone’s IMEI on the Device Check Canada website: https://www.devicecheck.ca/check-status-device-canada. You have all this information provided on the following faq link: https://fizz.ca/en/faq/how-do-i-unlock-my-phone.

Can you try to insert a SIM card from a different provider in your phone and see if you'll encounter the same message. By doing that, you'll be able to figure out if it's a phone or a SIM issue.

If you have a Samsung probably the PUK is not the SIM PUK, but is the unlock code

Contact Samsung to have the unlock codes (link)
Power off your device and insert the SIM from your new service provider.
Power on. If your device gives the following message you need to enter the MCK. "SIM network PIN blocked. Enter SIM network PUK." (See step 4 if your phone asks you for a SIM Network unlock PIN).
Enter MCK. It will likely tell you the code was "unsuccessful" however disregard this.
You should now be at a new screen which asks for the "SIM Network Unlock PIN." Enter the NCK here. Note you only get one chance to enter the NCK, so do NOT make a mistake.
You should see a message saying "Network unlock successful." Your phone is now unlocked.

Unfortunately that seems your phone is locked,
As already explained you should contact the previous provider of that phone