I have been receiving intermittent problems making calls. The message states that the number is invalid. At times I can use the re-dial function on the phone and get connected, on other occasions the call will repeatedly fail to connect. The numbers being dialed are mobile and land line. The "VOIP" LED is showing a constant green. The modem is a Huawei HG-658.   I have not noticed any interruption to the data service.   I have searched the forum, but not found a solution   Thanks for your assistance,   James ... View more