You can't set and fetch the same cookie in the same request. Unless you've previously set the cookies correctly (and I don't believe you have, because I think the error message will hit the browser before the headers, though I could be wrong about this if you're using a weird HTTP server I've not seen before but take it as a rule of thumb anyway), $cookies{ID} will be empty.

Even if you have set the cookie successfully, you have no control over what the client does with it. You have to check that you've retrieved a cookie successfully and you have to be ready to do something sensible if you haven't.

if (exists $cookies{ID})
{
    my $id = $cookies{ID}->value();
    # do something here
}
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