Hi, > I presume you have /etc/nsswitch.conf configured to use sssd for user/group > resolution, and that you have 'auth_mech: unix' and 'unix_group_enable: 1' > set in imapd.conf. > > If you do not make use of group based ACLs, consider turning off > unix_group_enable. If you do make use of it, use pts/ldap. "Unix" group > resolution can be very inefficient, as you would typically iterate over an > entire group tree to resolve group membership on each authentication. "unix_group_enable: 0" solved my problem, thank you ! What for is the "auth_mech: unix" ? For group management I understand, I can have a mailbox for a group, then imap needs to know who is member of this group. But with "unix_group_enable: 0", what for is the auth_mech needed ? When I shut down the local user management (sssd), everything seems to work. Thanks