why some sites in networks appears offline and some don't

I have a network. why some sites works and some dont. Is because the sub-domain.
https://lewistower.vppromo.in/ this site it shows offline but is like 5 sites out of 70 active sites, but when i click https://amytheone.vppromo.in/ another site it works fine.
sites that dont work:
marsha.vppromo.in
lewistower.vppromo.in
katbro.vppromo.in
jjsgang.vppromo.in

please help me. why others 70 sites works and out of nothing i create this and dont work.
thanks