If your Wi-Fi SSID is not showing up on your D-Link extender, it may be due to several issues such as incorrect configuration, firmware problems, or signal interference. Ensure that your extender is properly configured and updated to the latest firmware. Check for any signal obstructions and make sure the extender is within the range of your main router. For further assistance, contact the D-Link support team at the toll-free number +1-888-899-3290 to resolve the issue promptly.