@MissedTheBeat Sadly, no reply. I'm really getting fed up with TPLink support. Seems I know more about their products than they do. 

Every time I seek assistance, they are reading from a script, ignoring the fact that I've already provided them with the answers to their questions. 

Then, I'm met with an endless barrage of idiotic suggestions (did you unplug the router???) before they "escalate" the issue and I get no response. 

Good luck. As for me, this will be my last TPLink product. I'm not going to support their subscription based feature availability. 

As stated in my original post, the WAN IP address is correct. I'm using the dyndns updater client on the server and the router has my dyn credentials. IP address is confirmed correct on dyn's web portal. Also as stated in my original post, port 3389 is port forwarded to the server's internal IP address, which is static. Server's firewall rules do not need to be reconfigured since they have been working for the past 10+ years on my last two routers. I can RDP to the server inside my network using the server's internal IP address, but I cannot connect using the dyn host name, either inside or outside my network. Again, WAN IP is confirmed to be correct on the dyndns web portal. .

 @terziyski 

Thanks for the reply.

I checked the following:

1 - WAN IP address is the same as the dynamic ip address used. This has been checked using a dns lookup tool. The router has the dynamic IP setting to the service provider (NO-IP) and the status is marked as 'Success!' in the dynamic DNS page of the router settings.

2 - Port 3389 has been forwarded using the 'Port forwarding' section of 'NAT Forwarding' of the router settings page.

3 - Port 3389 is enabled. This can be proved because I can use RDC when connected on the local network.

In addition, I have reserved the device IP in the DHCP section of the router settings and bound it to the MAC address to ensure the local IP address does not change.

Any further suggestions would be welcome.

Many thanks

  @terziyski 

Thanks.

I can confirm my public IP address is the same as the DDNS address.

I confirmed by looking at the status page of the router showing the IP address and using external IP lookup tools to double check.

By using a DNS lookup tool, I confirmed the DDNS URL I am using also has the same IP address.

The DDNS page of the router confirms the DDNS service is logged into and it reports 'Success'.

I appreciate any other things you can suggest to try.

  @terziyski 

Thanks for your help.

It's now working! But the problem was the Microsoft RDC app on my iPad. When I tried on my Laptop it works.

I did use the external port idea also. I think this might be wise from a security point of view.

I realised from reading your posts and links that the settings are correct. So it must be something else. Hence switching away from the iPad.

I am very grateful and owe you a pint.

Cheers