Hi,
I was using K2 v2.6.9 and Joomla 3.6.0. When I tried to post new item from backend it logged me out automatically. So, I upgrade my K2 to v2.7.1 and Joomla to 3.6.4.
Now I can post new items, BUT Image, Image gallery, Media, Extra Fields & Attachments tabs are blank. Can you please help.
Screenshot is here -
imgur.com/a/nhv2a