Cannot View Shared Calendar in Outlook 2013

Hi there,

I am using Outlook 2013 on Windows 8.1 Pro with a Office 365 Midsize Business Account.

Some of my colleagues have shared calendars (every one has more than one calendar shared) with me and I can't check them in the app. Every time I try to activate one of those calendars I get a message "Preparing Calendar for first use" and "We can't complete this because we can't contact the server now".

Just want to mention that the internet is working and on the webapp I can see those calendars. Is there anything that I can do?

Best regards,
Vlad