iPhone calendar "+" button to add events grayed out In my iPhone calendar, the "+" sign is grayed out and will not allow me to add an event.  I have tried going to calendars in iCloud (Settings, iCloud, turn on Calendars) and calendars was on, so I turned it off, waited a few seconds, and turned it back on; no success.  I closed all programs and rebooted the phone and still was not able to add an event into calendar,  also went to Settings, Mail, Contact, Calendar and all is on there as well.
I have Iphone 4s and this happens once or twice a year.I ignore signing in my emaail account when asked.This time I signed in to my account as if I wanted to send to my Calender and the plus sign turned back to red and now works.I don't normally sync to my account.I just keep info on phone.