Chime not connecting to a complicated passworda

So I’ve upgraded my mothers mobile broadband from Three and the chime just won’t connect I’ve logged into admin to create a much easier password without the symbols etc but unfortunatly Three will not allow me to change to a password that don’t have symbols. So basically I cannot use my chime any more ??? Does the chime pro allow a more complicated password ??? Because my 1st gen chime will not connect to my mums new mobile broadband, what a shame