I think I'm correct in saying all landlines are BT supplied and rented out to various companies Sky etc.
Intermittently for weeks but getting more frequent, when I phone landline to landline or mobile to landline , a message sometimes says, " this number has not been recognised ", this involves sky, bt, landlines and mobile, Tesco in my case to landlines. Either by direct dialling or using the phones phone book, so landlines seems to be the common factor, and is happening on outgoing and incoming calls, with people phoning me getting the same message.
I phoned BT for my brother and they said they found a fault, I phoned Sky for myself and they could not find a fault but would monitor my line for 1 week.
Is it a possibility that there is a problem for my area where I live that is affecting the telephone landlines of many people ?