Unable to remove Activation Lock from my iPhone

There is no supported way to downgrade from iOS 26 back to iOS 18. That has never been supported by Apple, so what did you actually do? Hopefully you did not download some ipsw file from a website that claimed to be signed by Apple.

I would recommend resetting the phone like Apple tells you and you will not be able to restore from a back up now. You will be back on iOS 26, but at least you would be able to use your phone if it works. It is possible that it won't work now.

Restore your iPhone, iPad, or iPod to factory settings using a computer - Apple Support

Just so you know, that does not restore iOS 18. When the beta version was being used, you could remove the beta to return back to the latest shipping release, but now the latest shipping released is iOS 26, and you cannot remove it.

What laptop are you using?

I would suggest to put your device in Recovery Mode and try the Update option first, then the Restore if not successful. It will take about 15 minutes for the OS to be downloaded to your device, so be patient. Follow the steps closely as the key presses must be done correctly. There is also the option on the bottom of the screen for service if the device is stuck in Activation Lock.

If you can't update or restore your iPhone or iPod touch - Apple Support

Bobth3build3r123 wrote:

Hello,I am downgrading from IOS 26 back to 18 and when I have reset my phone it says locked to owner and asks me for my email and password, i put in the information and I click the next button and it does nothing

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Original Title: Iphone locked to owner

Unless you were using Beta Software, the only path back to iOS 18 is to Jailbreak your phone. If you did that, you're on your own and Apple won't help you either. We can't help you.