What I did: Bought Premium, and use calendar feature
What happened: One calendar account doesn’t show up
What I expected: all accounts show up
Things that might be helpful to know (Agenda version, OS and model, etc):
If you go into the Calendar app, do you see the calendars there? You need to make sure Calendar app is setup, even if you don’t use it, because it sets up the shared calendar store for all apps.
I think the problem there is that the calendars in question are not editable. They are generated from other data, correct? Eg. Birthdays is taken from the Contacts app, I believe.
Yes, of course, the Calendar app shows everything as expected and the problem includes editable calendars, like the ones from iCloud (Personal, Work, etc).
No, the calendar comes from exchange work account
Unfortunately this might be a limitation set by your employer, have a look at this part in the How To section regarding exchange calendars: Dates, Events, and Reminders