[CentOS] Centos7 - Mate : screensaver troubles after Freeipa-config

Thu Aug 10 13:43:30 UTC 2017
johan.vermeulen7 at telenet.be <johan.vermeulen7 at telenet.be>

Hello All, 

these days one of my tasks is connecting some Centos7 laptops to Freeipa, also running on Centos7. 
After doing that, some users report nog being able to unlock their screens. 
Only after reboot are they able to login again. 

I see this em in /var/log/secure: 

Aug 10 13:34:37 **** mate-screensaver-dialog: pam_sss(mate-screensaver:auth): authentication failure; logname= uid=382900663 euid=382900663 tty=:0.0 ruser= rhost= user=***** 
Aug 10 13:34:37 **** mate-screensaver-dialog: pam_sss(mate-screensaver:auth): received for user ******: 17 (Fout tijdens het instellen van legitimatiegegevens van gebruiker) 
Aug 10 13:34:37 **** mate-screensaver-dialog: gkr-pam: the password for the login keyring was invalid. 

Out of the 50 people or so I now have connected to Freeipa, I received some 5 reports. 
All users are on fully updated Centos7 machines configured with epel-provided Mate desktop. 

I see a lot of these problems when googling this, but none in Centos. 

Help would be very much appreciated. 

Greetings, J.