Hello franci288,
Thank you for using Apple Support Communities.
We understand that you are trying to set up your new iPhone 12 and are transferring data from your old iPhone and getting a message that the setup failed and an error code -71163. We would first recommend taking a look at this support article to make sure that you are not missing anything in the process of setting up to transfer your data:
Transfer data from your previous iOS device to your new iPhone, iPad, or iPod touch - Apple Support
Once you have verified that you are not missing anything, you can use the information in the following support articles to address the errors that you may be getting:
If you see an error when you update or restore your iPhone, iPad, or iPod - Apple Support
iOS update and restore errors - Apple Support
Best regards.