Manual IP update for dynu.com - web
If you don't want to install Update Client - manual Update on your external IP...
instructions step by step:
1- Login to dynu.com
2- DDNS Service -> click on icon
3- Actions -> click on pencil for edit
3.1- on corner right on web page is your external ip now
4- select ip shown-recorded by server in the form on left and REWRITE the new ip
SAVE the form click on green button
that is a manual ip update
check the host now ....

DONE must all to be good now
THANKS and good Luck

Actually, you can also update the IP address just by putting it into an url like below:

https://api.dynu.com/nic/update?username=YOURUSERNAME&password=YOURPASSWORD&myipv4=216.34.23.98&myipv6=2001:4860:4860:0:0:0:0:8888

BTW, you can check your external IP address using below URL:

http://ipcheck.dynu.com
http://ipcheckv6.dynu.com

With this API typed in address bar you will update your dynamic ip.
But, who will remember this long url, and must typed correct.
I make HTML file and on start-up or clicked on desktop will update ip.
source is down just rewrite in editor and save with ext. HTML
replace YOUR_USER_NAME and YOUR_USER_PASSWORD with yours in code and will go...
do not use bold type
===============
*html>
*head>
*script type="application/javascript">
function getIP(json) {
window.location.href = 'https://api.dynu.com/nic/update?username=YOUR_USER_NAME&password=YOUR_USER_PASSWORD&myipv4=' + json.ip;
}
*/script>
*/head>
*body>
*script type="application/javascript" src="https://api.ipify.org?format=jsonp&callback=getIP">
*/script>
*/body>
*/html>
============================
NOTE: replace * in code with simvol for less look in refernce (here is not accepted symvol) will work in Firefox on mac - not tested on windows or linux
THANKS for API URL is good to think todo one updater for my old mac