I am using Office Professional 2010 (64-bit) and have my email in Microsoft Hotmail accounts (2 of them).
Outlook is linked via the Outlook Connector (64-bit) to enable 2-way sync of mail and calendar with my online Hotmail accounts.

I frequently, on my first attempt to access my Inboxes, get the error message box:
    "We were unable to sign into your account.  Please try again.  Could not authenticate against the Windows Live ID service.  Please try again later."   "OK"

Three times out of five, if I empty the Trash bin on one of my two accounts, synchronization will happen at least for one of the accounts.
What are possible causes of the error message?  I'm using Outlook to access my email with frustration on the extra tweaking needed to get the recommended tool (Outlook for Office) to work from nearly the first try with this combination of parts ('account'@Hotmail.com, Outlook Connector (64-bit) and Outlook for Office (64-bit).  I apologize if this is an old / many time posted topic, but after searching 5 times and not finding a similar post, I decided to put it out there.

MANY THANKS !!  for any help.