Use a standard USB-to-TTL adapter (Siudi uses 3.3V logic on the SWD/Serial header). Open SiudiStudio and select the correct COM port.
: Common identifiers include USB\VID_6244&PID_0531 and USB\VID_6244&PID_0530 . Connectivity : Supports USB 2.0 and Ethernet connections. Siudi 7b Driver
This is a very common error.
This can happen even when the LEDs appear normal. Use a standard USB-to-TTL adapter (Siudi uses 3