Three times yesterday I telephoned my wife. We both use the iD network. On each occasion I received the “number not recognised” message. These attempts were dialled from my mobile phone contacts list so it wasn’t a typing error and the log shows the attempts. In the end I had to contact her using WhatsApp which connected first time.
On returning home, I tried again and it work flawlessly. Exactly the same problem has presented itself today.
I noted that at least one other person had this problem although I don’t know whether they are now problem free. Are you able to provide a remedy please.