Hi,
First, forgive me for the mistakes, english is not my native langage ;-).
We manage computers for schools and some use Up Studio (Version 2.6.56.627). When they want to login, even with the proxy declared (the test is ok), they can’t. There is a message “Login failed”. They have problem too if they want to sign up.
As seen in another topic, we add in the whitelist of our proxy “www.tiertime.com” : same result.
But, if we install an old version (2.4.20.351), no problem, all works fine !
But we can’t use this old version because of the unsigned drivers, so we can’t do silent installation.
Any advice will be welcome 
Thank you