Hi  @h2ogeek,

If you're experiencing problems with the VPN Server/Client feature, we recommend reviewing the following troubleshooting articles for assistance:
For VPN Server issue on TP-Link Router: https://community.tp-link.com/en/home/forum/topic/653446
For VPN Client issue on TP-Link Router: https://community.tp-link.com/en/home/forum/topic/270268
These articles cover common issues related to VPN configuration, including:
   1) Remote phone/laptop fails to connect VPN Server.
   2) Remote devices connect to the VPN Server successfully but cannot access internet anymore.
   3) Remote devices connect to the VPN Server successfully but cannot access local resource of the VPN Server.
   4) VPN Client on Wi-Fi Router is not working.
 

 Hi @Joseph-TP ,

Thank you for your reply! I checked the URL that you provided, and I double-checked everything. everything is okay according to the VPN Server Is Not Working Properly on TP-Link Wi-Fi Routers document 

Step 1:

IP Address: 100.100.X.X -> OK

Step 2:

DDNS working 

* Tested that my domain name IP is equal to my public IP    -> PASS

* nslookup mydomain-> The address matches my public IP -> PASS

* I tried using UDP and TCP, and the result was the same.    -> FAIL

* I know that still blocked because I tried telnet mydomain 1194 -> I got Operation timed out
telnet: Unable to connect to remote host

h2ogeek wrote

 

Step 1:

IP Address: 100.100.X.X -> OK

 

  @h2ogeek 

Hi,

This is NOT a public IP address. The range 100.64.0.0 – 100.127.255.255 is being used for CGNAT.

That is the reason why you cannot reach your VPN server via the Internet.

Please follow the suggestions in the link that @Joseph-TP posted earlier.

  @woozle 

I did not show the last octets because it is a public address; that is why I added the X.X to represent those octets. I only left the first 2 octets to show you that this is a public address

  @h2ogeek 

Ok, but it doesn't matter what the numbers for the two "X" actually are. If the "Internet IP Address" shown by your Archer GX90 starts with 100.100. ..., then this IP address is an internal IP address of your Internet Service Provider's CGNAT, but not a public IP address that can be reached from the Internet.

https://en.wikipedia.org/wiki/Carrier-grade_NAT