Dnsutils doesn't work in RPi3

Hi ~

GCS has DDNS domain name so I’ve been using dnsutils’s dig command to capture GCS’s dynamic IP address on RPi 1 model B.
The problem came out with migration to RPi3 with dig command in rc.local.

With this rc.local, it shows below error on booting RPi3 saying rc.local didn’t executed

But when I tried on command line in SSH it works fine as below

What did I missed?

Very appreciated if you guys let me get on track ^^

Check the log using journalctl for more information. And possibly the systemd logs with systemctl status rc.local