Thanks for your response.
1) logging out
2) closing the browser
3) logging in again
4) and Giving permission of managint he sprints to Administrator group
solved the problem.
I was under the impresssion that Admins can manage the sprints on any proect by default.
Badges are a great way to show off community activity, whether you’re a newbie or a Champion.Learn more
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG