Problem adding USER to MQTTClient

[giovanidiaz]

Hi, I need define specific USER for connect to UBIDOTS, it is a TOKEN, but when try I get error: TypeError: object of type 'NoneType' has no len()

I change the last five number of my token, but is similar of this:

USER = 'BBFF-YqUfgtaby7Gs4W4pSTIMZnyDa00000'

I probed with:

client = MQTTClient(client_id, hostname, PORT, USER)

I hope that you can understand me, really Im new in python.

Im working with digi 3G Global Cellular, and if I quit the USER, all works.

If you can help me I really apreciate it. Thanks for all.