Server status page / recovery server

I've been trying to re-install my iMac's OS, having already erased the HD - so no going back. In recovery mode I keep getting 'The recovery server could not be contacted'.

When I look at the server status page, the recovery server is not listed. Does this mean it no longer exists? is that the problem?

I've tried most things I've seen suggested to cure the problem eg checking the internet connection, syncing the date to apple servers, setting an earlier date, trying various key combinations with "r" etc., but nothing seems to work so any advice gratefully accepted.