Just wanted to say had almost an hour with the support team this afternoon, and the problem now sorted.  Thanks very much for all your help. 

This had been working without a problem until last week, when we started getting an authentication error message - I had made no changes to the settings.  I contacted my domain provider who indicated all was well at their end.  I tried re-entering the password, but could not get it to authenticate.  I now get a EOF on Socket message.  What has happened.  Can you please help.