The library file sssd_krb5_idp_plugin.so path is /usr/lib/x86_64-linux-gnu/sssd/modules/sssd_krb5_idp_plugin.so But in the shipped configuration file /etc/krb5.conf.d/sssd_enable_idp the library path is set to /usr/lib64/sssd/modules/sssd_krb5_idp_plugin.so so the authentication to external identity providers fails: when the user tries to login pam_sss.so authentication module doesn't print authentication instructions at the login prompt. As a workaround I created the following symlink: ln -s ../lib/x86_64-linux-gnu/sssd /usr/lib64/sssd In this way the authentication to external identity providers works.