Ever since my recent upgrade to ios 7.1 on my iphone 4s, I can't add new calendar events

Nor can I add a reminder on the Reminders app. New events/reminders just disappear. Both worked well prior to the upgrade. Is this a known bug? I have tried changing sync, switching calendar and reminders off, then back on, refreshing the calendar, quitting the calendar and reminders apps from the home screen and then restarting them. I powered down the phone to reset it. Nothing worked. Can this be fixed? All reminders/calendar events scheduled previous to 7.1 alerted as set. I just can't create new events. Thanks