Normally a sign that the PC isn’t communicating with the stand
Check you are using the correct USB cable
The Mecmesin USB-Serial cables (432-450) all use an FTDI chip with a VCP (Virtual COM Port) driver.
We recommend always using a Mecmesin supplied USB-Serial cable but if a decision is made to source a USB-Serial cable from another supplier it must use an FTDI chip.
If any replacement cable does not have an FTDI chip it may be problematic and is likely to lead to support issues.
Once you are using the correct cable, Update the FTDI driver (see below), If a new install, check the correct driver has been assigned