Temporary error 16

When I try my webmail on the BTYahoo site I get temporary error 16 and am told to try later. This is happening a lot these days - Google doesn't really tell me much, so anyone got any ideas?

Browser version? I once fixed someone's broken webmail (can't remember which ISP) by upgrading them from IE6...

http://help.yahoo.com/l/us/yahoo/mail/ymail/taes/mlt...

Thanks for that useful link. I actually use IE9 with Windows 7 so I'm OK there. I tried clearing my Temp files and cookies and that seems to have worked. Interestingly I was using webmail whilst OE was set up on another machine to download BT mail - I think this has happened before and it seems that it only likes to be accessed from one machine at any one time. I like the new webmail interface by the way - anyone know of any glitches?