Hello, friend!
There are two reasons for the failure.
1. The port is occupied.
2. No service is set up on the device.
You can use the following template to verify:
1. The CPE dials up successfully and obtains the WAN IP address.

2. Create a port forwarding rule on the UI.
(1) Run the ipconfig command to obtain the IP address of the localhost.

Enter ipconfig in the command line to obtain the local IP address 192.168.8.100.
(2) Set the port forwarding configuration on the UI.

WAN port indicates the WAN-side port, LAN IP address indicates the local IP address, LAN port indicates the LAN-side port, Protocol indicates the protocol corresponding to the port forwarding rule, and Status is enabled.
(3) The network topology is as follows:

3. Create LAN-side services through IPOP for WAN-side access. This document uses the web service as an example. The value must be the same as the LAN-side port set in step 1.
(1) Create a local HTML file named default.html.

2) Use the IPOP software to set the HTML port to the local port 8080 (8080 is the UI setting).

Root Dir is the path of the default.html file in step 1, Port is the LAN port set in the Port forwarding rule, and Default Page is the HTML file name default.html. After setting the three parameters, click Start.
4. Access the local service and check whether the access is successful.
Enter http://192.168.8.100:8080 (192.168.8.100 is the local IP address) in the address box of the browser and check whether the login is successful.

5. Access the local service from the remote server and check whether the access is successful.
Open a browser on the remote server, enter http://5.5.7.53:19080 in the address box, and check whether the login is successful.

If this is successful, the port forwarding function is normal.