Empty contacts site after update to 15.12

Helly everyone,
I updated my nextcloud from 15.05 to 15.12. but now my contacts site is empty/white. How can I solve the issue? The nextcloud.log provides no entries :frowning:
Thanks a lot

There was a bug with Contacts 3.1.4 and Nextcloud 15.
Upgrade your Contacts app to 3.1.5 and the problem should be solved.
Ref: https://github.com/nextcloud/contacts/issues/1278