After a fresh install of Trixbox 2.8.0.2 I could not get CDR to work in the PBX section. Took some digging to find out but well worth it. CDR is really an important feature. The following link helped me http://trixbox.org/forums/trixbox-forums/open-discussion/there-no-cdr-report-tb-2802-tb-2801
I finally reproduced this here. I updated from asterisk16-addons-1.6.0.2 to asterisk16-addons-1.6.0.3 and now it’s working.
yum update
reboot