It can be anything! An apex, subdomain, or even a URL.
Results forres.outlook.com.prod.o365proxy.firstabudhabibank.myshn.eu
www.res.outlook.com.prod.o365proxy.firstabudhabibank.myshn.euoutlook.com.prod.o365proxy.firstabudhabibank.myshn.eucom.prod.o365proxy.firstabudhabibank.myshn.euprod.o365proxy.firstabudhabibank.myshn.euo365proxy.firstabudhabibank.myshn.eufirstabudhabibank.myshn.eumyshn.eueu