Since 9.1 can't share calendars and can't change shared properties

Server
,
3

Steps to reproduce

  1. can’t share calendars

Expected behaviour
write user to share to but nothing happens

Actual behaviour
Nothing !!

Server configuration
Operating system: debian
Web server: apache
Database: Mysql
PHP version:
ownCloud version (see ownCloud admin page): 9.1 stable
Updated from an older ownCloud or fresh install:
update from 8.0.2 with all intermediates
ownCloud log (data/owncloud.log, see How to find webserver or OC logfile / enable php logfile):
no
Special configuration (external storage, external authentication, reverse proxy, server-side-encryption):

Integrity status for oC9+

Login as admin user into your ownCloud and access
http://example.com/index.php/settings/integrity/failed
No errors have been found.