I have a pair of CPE 210   which the access point is being connected to switch port.The led port of the switch port is not permantly lit for the link but it goes off for long time with result cannot connect through the other site.The switch type which is being connected is TL-SF1005D/TL

I have changed ethernet wires but the problem remains.I have the pair 4 years.

What is your advise?Is there a problem with the device?