I have same problem Before i know the problem, my code like this.
$user = Socialite::driver($provider)->stateless()->user();
$existingUser = User::where('email', $user->email)->first();
on my history error happen in method user() after stateless() the problem happen when user click button cancel in sign in to process on page login with google. As we know, after you choose your email will redirect you to choose new page with option Cancel | Continue
so we apply try catch like this
try {
$user = Socialite::driver($provider)->stateless()->user();
} catch (\Exception $e) {
return redirect()->to('https://blablabla.id/login');
}
and it solved. So, thank you sir. I hope my description for this issue make help someone.