Are you connected to the internet right now? I can detect low resistance on the line which is possibly caused by a issue with a device connected to the socket, broken filter, or issue with the phone socket.
The connection and speed from the exchange to the modem is okay, but the authentication or allowing of the system to connect appears to be having an issue. The possible cause are stated above or the modem.
I've made advjustments on your signal to noise ratio to help with the stability. Please observe the connection and advise us if the issue will persist.