Problem converting singlesite to Multisite

Today we have done a modification to pcmages.gr
This site was running wordpress simple and we configured it to be
converted to multisite.
The client needs to have these multisites:

http://www.pcmages.gr (original site)
pro.pcmages.gr (new site)
remote.pcmages.gr (new site)
eshop.pcmages.gr (new site)

i have gone through the instructions here: https://premium.wpmudev.org/blog/ultimate-guide-multisite/?ht2=1&utm_expid=3606929-52.ZpfeUjXqSWOCaoohIqoFQQ.1&utm_referrer=https%3A%2F%2Fwww.google.co.in%2F

It seem that it's working ok as it is shown here: http://prntscr.com/87nd5w

but the problem is that it cannot resolve these domain names:

pro.pcmages.gr
remote.pcmages.gr
eshop.pcmages.gr

Any suggestions on how to fix that so that when i click on a multisite it doesn't bring a 404 page ?

Probably a problem with the .htaccess ?