What should I do if I cannot access the router's web interface?

First, ensure the connection between your PC and router is correct by checking if the LAN port LEDs are lit. Verify your PC's TCP/IP configuration is set to automatically obtain an IP address or is manually set within the 192.168.0.2-192.168.0.254 range. If the modem's IP address is 192.168.0.x, the router will automatically switch to 192.168.1.1 to avoid IP conflict, so try pinging 192.168.1.1 instead.