did you try to enable the wifi on the iPhone, probably you need to get the authorization from apple
When you bought your iPhone? Before 2016?
Thank you for reaching out to us with this case.
As you can also find out from the link below, your phone should work just fine with the Fizz SIM card inside it: https://fizz.ca/en/faq/compatible-devices.
I'd recommend you also contact Apple and ask them for a Network Unlock PIN that will allow your phone to be used at FIZZ. It is, most likely, locked by the manufacturer from being usable under any mobile service provider and unlocked just for some.
I hope you have a pleasant day!