Hello there. I'm unable to call out of an analog telephone on my 4g router but calls can come in. I have turned on volte but it is still not calling out I should have volte as I received the email from lebara saying it was active but it is not work I get a steady slow tone when I pick up the receiver and when I dial it goes silent for a moment before going back to the constant tone or I get a fast busy tone. It is an older bt phone I am using to test my system but plan to use an fxo to connect to my pbx.