why iphone 13 with ios 16 not accepting right passcode and became unavailable

That cannot happen. The phone KNOWS the right passcode. It is stored in the Secure Enclave and can only be changed by entering the correct passcode, twice. Your device is the master, not you. And it’s why it is incumbent on every owner to make regular backups, for the situation where a wrong passcode is entered too many times.

Whether you accept the truth or not doesn’t matter. You need to follow the instructions to restore the phone. Note that the first approach below does not require a computer.

If your device has iOS 15.2 or later installed, check out this link→How to reset your iPhone, iPad, or iPod touch when you forgot your passcode - Apple Support. Otherwise:

See this Apple support link→If you forgot the passcode on your iPhone, or your iPhone is disabled - Apple Support

Or watch this companion video ⬇️

After restoring the phone using one of the methods above you can restore your most recent backup.

If your device says unavailable, it does not believe you have entered the correct passcode. Why, we can't answer. Perhaps someone changed your passcode or you have entered the wrong one.

You can reset it since you are on iOS 16, by following the directions here --> How to remove your iPhone, iPad, or iPod touch passcode without a computer - Apple Support

Hello ~ Someone entered your passcode incorrectly too many times. Take a look here…

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

~Katana-San~

You are not speaking with anyone from Apple here. This is a user to user only forum. We cannot reproduce or check anything on your phone. If you'd like Apple to do that for you, feel free to schedule an appointment at your Apple Store Genius Bar.

Hello ~ I would suggest you take your iPhone in for a checkup …

Genius Bar Reservation and Apple Support Options - Apple

Also go to upper right hand corner and then click on Get Support for more assistance from Apple Support.

~Katana-San~

Actually, in this user’s defense: it absolutely can & did happen. I just updated iOS on my old iPhone XR for my son to start using. I had erased all content & settings, absolutely no settings remained from my use of the phone. I input his Apple ID, & linked it to FindMy, then immediately began updating iOS. During the initial phase of update, I opened the phone several times to check status without any use of a passcode. So I know for certain there was no passcode set up prior to the update. As soon as iOS 15.2 had installed, the phone began asking for a 6-digit passcode, which has never been set up on that device. Even when it was my primary device, I only had a 4-digit passcode set up on it. Some Google results stated that a few users were able to input generic codes such as “000000” or “123456” when this happened, but I was not one of the lucky ones.

I had originally been able to reach the Lock Screen showing the “erase iPhone” option located in the bottom right corner after the first few attempts at guessing the passcode it was asking for. Unfortunately the phone would not recognize me trying to select “erase iPhone”.

Currently I am in the process of erasing the device via MacBook. I was unable to erase iPhone via iCloud/FindMy because the device went offline after a few attempts of & will not connect to wifi again until it is unlocked. This is the second attempt at erasing via MacBook because as soon as the restore process completes, the device turns on & immediately shows the “iPhone Unavailable” screen once again.

appanparige wrote:

someone changed your passcode or you have entered the wrong one -- Both didnot happen

no one touched and stil i remembered passcode.

OK.......That doesn't help you though. You will still HAVE to follow the directions in the link both Katana-San and I provided you.

No worries. Take care.