Set everything back to factory default in MSI Afterburner and on your GPU Card.
The RX580 has feature similar to Zero RPM which means that the fans only turn on when the GPU card reaches a certain temperature.
To check to see if that feature is working normally and both fans are working I would Stress test the GPU card and see if the Fans start working after reaching a temperature ~58C - 60C and above.
IF the GPU temperature is above 65C and none of the fans are working then you have a problem. Could be driver, defective fan, or GPU Card.