1. The touchtone on that phone might be off. If that phone is giving a problem when forwarding, remove forwarding, swap with another phone and try again.
2. Do the dialing slowly and deliberately. Not saying someone is incompetent, but in desperately looking for answers, maybe someone is dialing fast and the Toshiba is not getting digits slow enough, not likely, but slow and deliberate is better anyway.
3. Put a pause character after the 6011 and after the 9. Might not help but you can see the first time you try it.
