I try to reinstall the macOS High Sierra on my computer after I factory reset it and it just tells me “the recovery server could not be contacted “
I’m trying to sell the computer but I can reinstall the thing now
The only practicable way to install High Sierra on that Mac is to ask an Apple Store do it. Or, create a "bootable USB installer" from another Mac actually capable of booting High Sierra.
Apple silently and without explanation removed the High Sierra installer from their Recovery servers several months ago.