The APN settings can be checked and changed, following bellow steps:
1) Connect to router trough WiFi
2) Open browser and go to http://sentinel.home/ to access settings
3) In the upper navigation menu select User > Login, input username "user" and password "user"
4) In the field "Mobile Connection" select "Settings", this will brought up the screen showing APN settings
5a) If you use A1 (previously VIP) SIM then input "internet" for APN and leave username and password blank
5b) If you use HT SIM then input "internet.ht.hr" for APN and leave username and password blank