|Is this a new router or has the problem suddenly come along?|
Simple thing first is to power off the router for about half a minute then let it come back on again (takes a minute or two).
Otherwise, depending on the background to this, use the full reset here on page 8:
Looks like a pin hole to the far left of the power plug (viewed from the rear).
Always pop back and let us know the outcome - thanks
message edited by Derek