how do i recover my skp file if file showing this " this does not appear to be skp model "
It generally cannot be recovered. Sometimes @colin can recover some parts. Your profile is incomplete and unhelpful, are you on a Mac or PC? Have you tried the backup file?
Your profile says you are using SketchUp 2021. Are you using a cracked version of it? What operating system? 2021 is not an operating system. Where have you been saving the file while you are working on it? Share the file. Maybe we can get something from it.