If you are connecting to the second or third robot (lab=2, lab=3), you need to change the TCP port using the following command:

r'portnumber 3331  ; for lab=2
r'portnumber 3332  ; for lab=3
r'portnumber 3333  ; for simulated robot 1
r'portnumber 3334  ; for simulated robot 2

Note: the default port (that you normally do not need to specify) is 7123.