[SR-Users] Pseudo-Variable {$au} is NULL

Hi All, I am updating our Kamailio from 4.0.6 to the latest 5.2.2, we use kamailio as LB in front of two asterisk server. My problem is that during registration forward to the asterisk servers {$au} is NULL This is the code we have, which is the one you find in most documentations $uac_req(furi)="sip:" + $au + "@" + $var(rip); I logged some Pseudo-Variable to see their contents: {$au} NULL {$aU} NULL {$Au} username(a)domain.com {$fU} username {$oU} NULL {$ru} rU: {sip:domain.com;transport=UDP and ended up doing this which works $uac_req(furi)="sip:" + $fU + "@" + $var(rip); Any idea what could be wrong? Thanks, Daniel