Found my lost phone

Did you go to the Web site and follow the instructions there?

That link is for this Support article: Return a lost, locked iPhone - Apple Support

I'm making an educated guess that you had AppleCare+ with Theft and Loss Coverage, and that you used the theft and loss provision. It might be that the reason why you can't enter your Apple ID and Apple ID password is that the terms of the Theft and Loss coverage say that the insurance company now owns the phone.