>>>>I would start with looking into an error message/status which should be in client properties, I guess
>>>
>>>Right. I checked the properties of Client, could not find anything.
>>>
>>>Thanks.
>>
>>You should have error in the exception in the catch block then
>
>Right... In fact it turns out that it's Google that locks the access to the account when it thinks the account it's bein hacked. There seems to be a procedure for this kind of situations. Thank you very much for your help.

you are welcome