Team Calendar asks for password every 30 seconds in Outlook

I connected my Team Calendar from the Office 365 Team site to Outlook (using Version 2013) and now it asks for my password every 30 seconds. If I delete the calendar from Outlook, it no longer asks for the password, but every time I try to reconnect, it continually asks for my password over and over about every 30 seconds. Anyone have any ideas?

Paul Collings