Troubleshooting Alist Service Port Forwarding Issue with OpenWRT Router

I recently purchased a GL.iNet MT3000 router, which comes with the open-source OpenWRT firmware pre-installed, and successfully deployed the alist service. The server is accessible via a public IP address and DDNS. In the current situation, direct access to the router's web interface is possible by entering the domain name or public IP address in a web browser. Furthermore, accessing the alist service by entering port 5244 is also possible directly. However, I have set up port forwarding with an external port of 6666 forwarding to the 192.168.8.1 IP address on port 5244, but the setup does not seem to be working as expected. I am seeking assistance in resolving this issue and identifying the root cause of the problem.