calendar, icloud, server errors

My calendars have not been updating between my devices. Mac Mini, 2 iphones, ipad and icloud. When I try to edit or add an event I get the message "The server responded with an error". "There is insufficient storage space for ..... in account iCloud". I have signed in and out of icloud on the computer, iphone, and ipad. I have turned off and turned on Calendars. I also cleared the cache and deleted the preferences. I have 2 TB of space with 248 GB used on iCloud. This had been going on for over a week and I need help!!