Openstack Xena: error deleting image and snapshot via dashboard (as user and as admin)

Hi all, we have installed Openstack Xena in our cloud infrastructure (OS Centos-Stream 8) and we find a problem with the delete of images and snapshots via dashboard. The delete command returns "Error: Unable to delete Image:xxx" Via command line the delete works well. Looking in glance logs  I don't find any error message. Did you experienced this problem? Have you suggestions about it? Thanks, cheers     Federica -- Federica Fanzago INFN Sezione di Padova Via Marzolo, 8 35131 Padova - Italy Tel: +39 049.967.7367 --