Delegated calendar issue with Calendar app on OS X

Hi,

In our small office (3 people), we all share our Office 365 calendars with read/write permissions. We use Calendar app (7.3) on OS X (10.9.4) to manage those calendars.

All of a sudden this morning, my delegated calendar became unreachable for my colleagues (no access at all) on Calendar app while permissions are correctly configured in OWA.

Only my calendar seems affected and I can still see and edit my colleague's calendar.

My colleagues can still see and edit my calendar on OWA... but not with Calendar app anymore.

2 weeks ago, I had to delete and recreate my account using Powershell command (same username)... might be related to the problems I am now facing ?

Thanks for the help.