Unfortunately, without further information, it is difficult to determine the exact cause of the issue. However, some potential reasons for the optec remote not connecting to the LED sign despite using the correct port might include a faulty remote or LED sign, incompatible software versions, or incorrect settings/configuration. Troubleshooting steps such as ensuring proper power supply, checking cable connections, updating software/drivers, and consulting the product's documentation or support resources could help resolve the problem.
