1) Android
Turn on NFC on your settings
Please use Standard mode so your device an read the NFC chip in the Nemo Card
Check again if you turned on the Standard mode when the Nemo Card is not readable.
2) iOS
NFC function is always on for iPhones
You don't have to turn anything on. The NFC sensor for iPhones is normally at the top of the backside of the device. However, the function is only available for iPhoes using iOS 13 or higher version. If the NFC function is not working, please check with the Apple Customer Service or check if your device is NFC supported.