I'm not able to change working days in the project calendar, or create a new calendar for that matter. I've set myself to have all permissions (we manage this through PWA, as it is the only Office 365 product we're currently using):
However, I still get the following when I try to change anything in the calendar in Project Professional when logged in (note the inability to Create New Calendar or Add Calendar to Enterprise):
This happens even when I have "Allow Manage Enterprise Calendars" ticked in Global Permissions in PWA. I'm sure there's something I'm missing along the way...hoping for some help!