I have a problem on a TDA100 with forwarding a certain ext to cell phone. The system has a PRI with DID's. All the other extensions can be forwarded to a cell phone with no problem. To forward they dial Intercom *71029 and cell number and #. On ext 8469, when it is forwarded and you call it, you get the phone company message, " the number you have dialed is not in service". If you take the forwarding off and dial the number it works fine. Does anyone have an idea what could be the problem. Thanks