Id code

What is the error message you received? Here is advice from an Apple support page that explains what to do for a couple different messages:

If your account has been disabled for security reasons

If you see one of the following messages, your Apple ID automatically locked to protect your security and you can't sign in to any Apple services:

• “This Apple ID has been disabled for security reasons”
• "You can't sign in because your account was disabled for security reasons"
• "This Apple ID has been locked for security reasons"

You need to reset your password to regain access. Learn how to reset your password. 

If your account has been disabled in the App Store and iTunes Store

If you see a message that says your account has been disabled in the App Store and iTunes Store, contact Apple Support for help. 

If you are talking about the passcode that unlocks the device then you would need to restore it to fix the issue. See this article: If you forgot your iPad passcode - Apple Support