NetTV-App YouTube don't allow special characters for login / password like "+"

Net TV YouTube Anmeldung / Passwort mit Sonderzeichen ist nicht möglich.

I had a lot of troubles, E-Mails and phone-discussion with Philips Help Desk
about "sign in" to my YouTube account via the Philips NetTV App.

My problem was, I could not sign with my Google-login-data to Net TV App YouTube.
Via Internet it worked well also to the Philips NetTV App Picasa.

I have found the reason and the bug:

The Philips Net TV YouTube App. don't allow special characters like "+"
in the password.
Internet YouTube allows special character like "+" .

My TV:
SW: Q5551-