What is the serial-to-USB converter on the board? It's the IC closest to the USB port.
- If it's a CH340 you can try to rollback the driver. See Port monitor error: command 'open' failed: Invalid serial port. Could not connect to COM serial port - #49 by ptillisch.
- Not wanting to be the bearer of bad news but be aware that you might have damaged the serial-to-USB converter due to wiring mistakes. We don't know what your last project was when you did not have a problem and we don't know what your current project is.