get rid of pop up sign in

Outlook 2010 Instructions:

File > Info > Account Settings > Account Settings > Published Calenders Tab > Remove any calender(s) as per your needs.

Same problem here. I'm sharing my calendar and have 6 colleagues which are sharing theirs. 

Pop ups asking for credentials several times a day... 

PLEASE how can you stop this ?

Microsoft, in its infinite wisdom, has apparently turned off the calendar sharing servers at Office.com in order to force people onto Office 365.  You can no longer publish shared calendars to the Web in Office 2010 or earlier or in the retail version of Office 2013.  The popups are asking for credentials to a service which no longer exists and they keep coming back because there is no server to respond to the sign-in attempts. The only way I've figured out to stop the popups is to go to Accounts -> Account Settings -> Pulished Calendars tab, select the shared calendar and click "Remove."  A dialog box will pop up asking if you want to leave the calendar on the server but stop publishing to it.  Answer "yes."  If you tell it to remove the calendar from the server, it will go through the whole credentials request thing again and when the log-in fails you'll be back where you started.  Leaving the calendar on the server is okay in this case because it's actually already gone and there's nothing there anymore to delete anyway.  This turns off future attempts to log-in to the server to update the published calendar but doesn't help us who need that functionality and have now been orphaned.