Can not set Voltage on a Keithley 2380-500-15

I have been trying to control a electronic load system from Keithley but am unable to set voltage manually or using py-visa. 

Here is some code that just receives errors:

def set_voltage(user_input):
import visa
rm = visa.ResourceManager()
inputs = rm.list_resources()
usb_port=(inputs[0])
keith = rm.open_resource(usb_port)
print(keith.write("*VOLT " + str(user_input)))

set_voltage(1.0)

import visa
rm = visa.ResourceManager()
inputs = rm.list_resources()
usb_port=(inputs[0])
keith = rm.open_resource(usb_port)
print(keith.write("SYST:ERR?"))

Both say status success but then an error appears above the screen.