It is happening with my device too. Checked all the settings, disabled DDNS, the firmware is up to date, yet I am getting these weird error logs very frequently.:mad:

Captain here, there is a UX issue in the TP-Link UI that probably is causing your troubles. Go to your 192.168.0.1, log in and check the Dynamic DNS section. Under Service Provider, select all the other options one by one and make sure none of them is Enabled and Logged in. Log out of every single one and save (save each time to be safe). At this stage if you check your log you will not get any more DDNS error messages.

Then log in to just no-ip.com or whatever service you are using from that drop down. Assuming your other settings are fine, like Forwarding > [your entry]'s Status is set to Enabled, you have a IP & MAC Binding entry as well, your IP and MAC are entered correctly, then everything should work once more.

PS: How come the TP-Link Forums are not SSL/HTTPS enabled? How ironic, because the routers are not among the most unsecure ones on the market. :)

Thanks for the tip, it solved the problem!