I scheduled an event and saved it just now.    Subsequently, I realized that the event is recurring.  I don't see any way to add recurrence to the event.  Please make it possible to add recurrence to an event. 

I was trying to sync my calendar from my email service provider Posteo.de with OneCalendar. However, I get the following error message below. I get the same error when I am trying to sync my calendar on my iPhone. (I changed a few details in the error message where my user ID was shown.)

Could the reason be that there is something wrong with events that I imported from my old Google Calendar into my current Posteo Calendar?

Thank you in advance!