support please help: "the underlying connection was closed could not establish"

[alexvideogames]

when i want download files with phoenix file update option and write product code, UB wrote this error:
the underlying connection was closed could not establish trust relationship for the ssl/tsl secure channel

files dont loading

what this mean and what me do? few days before all be fine

[Ja\/\/aD]

1st update your box,
check your internet and antivirus/firewall setting,
go to tab bb5 --> maintenance and write any product code --> click on Get file list,
after that click on DOWNLOAD FILES,

if you face any problem please post here with screen shot