Cannot Re Install MacOs after re formatting the Hard Disk

I am about to sell my Mac and I thought I would reformat the Hard Disk and re install MacOs . However I cannot do this as I keep getting this error message . Safari will not load any pages although there does not seem to be any issue with the wi fi . I am able to boot into Recovery mode but I cannot re install MacOs and I cannot use Safari to get the Installer from Apple

Has anyone had this problem and solved it !