iphone not available

See the following (Step 5 in How to remove your iPhone, iPad, or iPod touch passcode without a computer - Apple Support )

5 - When your device restarts, follow the onscreen instructions to set up your device again, restore your data and settings from a backup, and set a new passcode.

Also see: Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Note that I'm not sure what access code you are referring to. A two-factor authentication code?

See instructions in: How to remove your iPhone, iPad, or iPod touch passcode without a computer - Apple Support