The box is connected by ethernet cable to the router, the IP Setup is on Auto and has not been changed.
The router shows that the box is connected but it can now take up to 10 minutes for a line to connect.
Up until recently lines connected as soon as the box was switched on

I have been using the same lines (1 x N and 1 X C) for months with no problems and the providers say that there are no problems at their end.

Other equipment connected to the router - a Smart TV and Youview box - connect to the network without problem.

I have done a factory reset but with no effect nor has a reboot or unplugging from the mains for 5 minutes.
I have also tried enabling just one line or the other but it makes no difference.

Could the box (4 years old) be faulty?