Is your modem a cable modem or ADSL one? If you modem is a cable one, you'd better try a MAC Clone on the TP-LINK Router.

yes!! Thank god, I upgrade the firmware, reset, and reconfigure the DDNS settings on the router, it finally works! Thanks so much for your suggestion.

the firmware version of my router is 3.9.2 Build 101230 Rel.40319s, Hardware Version R480T+ V4 00000000, it seems there is a new one to update. I will try and see whether it helps or not.

Ok. Now I have enabled the WAN Port 2 DDNS. But the DDNS accounts are fine, I have swapped and checked. Both accounts still working only in port one. Also If I try to change number of WAN ports this...

Region : Australia Model : TL-R480T+ Hardware Version : V4 Firmware Version : 3.9.2 Build 101230 Rel.40319 ISP : We are having an issue with setting up Dyndns account with model number TL-R480T+ We...