Auto update not working

Hi,
I can’t do an auto update for the plugin allthough my key is verified correctly.
On the plugin page it says “New Version…” and “Details …”, but no “Update now”-Link.
Why is it not working?
And I can’t check all the old posts with the same problem, becauce I am allegedly not logged in. But that’s not true, because otherwise I could not write this post.
Best regards, Kai