I can not restore my device with the serial number

Please click this link Restore your iPhone, iPad, or iPod touch from a backup - Apple Support and it will guide you so that you can restore your iPhone successfully from a back up on your computer or from iCloud. It will also give you information on how to handle errors while connected to your computer. Good Luck.

Axel F.

Restore from a backup, or... restore to factory settings? Could you please better explain what you're trying to do, and give us as many details as you can?

Thanks

Giulio