Calendar APP enabling impossible

After fresh install of Linux Mint 17.3 XFCE I've done an update to ownCloud 9.1.2 (stable).
After this I'm not able to enable Calendar APP and I'll got the error

"cURL error 56: SSL read: error:00000000:lib(0):func(0):reason(0), errno 104"

I've no idea how to solve this problem. Can anyone help?


the message should also include a link to where you can find a description of that error:


Failure with receiving network data.

Seems you have some network issues to the appstore at and/or

Thank you for your feedback.
The problem actually is a very slow internet connection. So I'll try to install the calendar app manually. The download with your URLs succeeded (very, very slow).