Save button for RT-AC68U DDNS settings?

[gatorback]

BACKGROUND
I have 'upgraded' a T-Mobile Cellspot to an RT-AC68U: http://tinyurl.com/asuscellspot The RT-AC68U was flashed with Merlin build 376.47. I have configured DDNS:

I did not see a 'save' button to save the configuration information nor did I see any actionable feedback from the router or the zoneedit site that the WWAN IP was updated.

QUESTIONS
1) Can anyone confirm that this feature (in Merlin build 376.47) is working correctly with zoneedit.com?
2) Is there supposed to be a save button?
3) What does the explanation mark imply in the screenshot below?

 

[Calisro]

The apply button on the ddns setup page is a 'save' button for hte config. The exclamation mark means that the configured hostname's in your DNS does not match the WAN IP address meaning it didn't update correctly. Check the log /tmp/syslog.log to see if there is anything of value.

 

[gatorback]

@Calisro: Thank you fro the /tmp/syslog.log suggestion.

Aug 29 07:43:18 watchdog: start ddns.
Aug 29 07:43:18 rc_service: watchdog 777:notify_rc start_ddns
Aug 29 07:43:18 start_ddns: Error ddns server name:
Aug 29 07:43:48 watchdog: start ddns.​

This has left me wondering how to interpret this into actionable corrective action.

As a 'bonus' I found these interesting logins from a Brazilian IP. Not if log entries indicates a successfully login:

Aug 29 07:25:07 dropbear[15345]: Child connection from 131.255.164.254:57553
Aug 29 07:25:08 dropbear[15345]: Exit before auth: Exited normally

Aug 29 07:44:06 dropbear[15423]: Login attempt for nonexistent user from 131.255.164.254:58655
Aug 29 07:44:07 dropbear[15423]: Exit before auth: Exited normally​

For giggles, I logged in remotely from public wifi (50.153.1.36:21632):

Aug 29 14:21:47 dropbear[17247]: Child connection from 50.153.1.36:21632​

Now wondering if it is correct to interpret:Aug 29 07:25:07 as successful connection from Brazil!?