Can't download materials from the cloud anymore

[ginovanta]

Hi guys,seems i've stumbled in the same problem as others: i'm able to login with my account credentials in the cloud but if i try to download any materials he asks me to login again and if i insert the same credentials as before it doesn't recognises them!It says that the server fails to authenticate..i've had this problem for a long time,any fix??
In alternative can someone suggest me how to make a fur material myself?Thanks