Newly added domain shows an old one

I am on Ubuntu 14.04 with Apache and have several virtual hosts on this droplet. All of them work fine, apart from the one I added yesterday which keeps loading the files from another existing site. The domain itself is not redirected, so I suspect there is either some sort of cache involved or (which is more likely) there is something wrong with the listener setup. It seems that the server just picks the first folder that comes after the 000-default in the alphabetic order and serves it when requests come for the new domain.

So to summarize it plain and simple, the situation can be described thus:

There are domains/sites A, B and C on the same droplet/IP. Having added domain D in the same manner as the other three, when I access http://(www).D.tld, the content I see belongs to site A.

I tried to remove it and then add again to the DigitalOcean DNS Panel, but nothing changed. Rewrote the virtual host directives several times, checked it in 4 browsers, cleared cache and still nothing. Any suggestions?