First you will have to verify that the issue is not caused due to some third party security software issue, this can be done by following the method:
- Check if your computer’s time and date is correct.
- Make sure you are logged in as an administrative user.
- You must have latest version of iTunes and the operating system should also be updated.
- Make sure that the modem firmware is up-to-date.
- Connect your PC with iTunes store without the internet proxy.
Sites which are trusted by Security Software are regularly provided with updates, if you update your iTunes software and sync your device with it, the issue will get resolved automatically when it will have security updates.
After updating the security software you will have to configure it. For configuration you will have to contact Apple by using port number 80 or 443.
If the above mentioned steps are not providing any help and Error 1 is still occurring then it means your device demands for service. After that you will definitely enjoy a trouble free service of Apple on your iPhone.