Shoutbox

80072efd

Could just be the server beeing off (fixes itself), if it lasts more than a day:

Check your connection (proxy) settings. Make sure there's no proxy set in tools > options > connection > advanced

In Internet Explorer: click Tools, then Internet Options, select the
"connections" tab. Try unchecking (if checked) "Use a proxy server for LAN" and check "Automatically detect settings". This should enable both Internet Explorer and Messenger to automatically find the best way to connect to the internet.

Now if you still can't sign in after that registering some dlls might
help (start > run > type: regsvr32 <name of dll> <enter>):
These are the dlls including the command to type after start > run:
regsvr32 Dssenh.dll
regsvr32 Gpkcsp.dl
regsvr32 Slbcsp.dll
regsvr32 Sccbase.dll
regsvr32 Softpub.dll
regsvr32 Wintrust.dll
regsvr32 Initpki.dll
regsvr32 Rsaenh.dll
regsvr32 Mssip32.dll
regsvr32 Cryptdlg.dll
regsvr32 Msxml3.dll

Good luck!