[SR-Users] radius_www_authorize error code -1

Hello! We are using radius_www_authorize() function to authorize incoming SIP REGISTERs, but sometimes happens case -1: for valid credentials (as I could see this in sngrep). And this time I did not detect corresponding Access-Request to RADIUS server side. Setting Kamailio debug level does not help to catch the real reason for this case in syslog. How to investigate this issue? Simple script example: if (!radius_www_authorize("$td")) { switch ($rc) { case -1: send_reply("400", "Bad Request"); exit; default: }; }; # -1 (error) - some error occurred during authorization (see syslog); [root@kamaili]# kamailio -v version: kamailio 4.4.2 (x86_64/linux) 892ad6 flags: STATS: Off, USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS, USE_RAW_SOCKS, DISABLE_NAGLE, USE_MCAST, DNS_IP_HACK, SHM_MEM, SHM_MMAP, PKG_MALLOC, Q_MALLOC, F_MALLOC, TLSF_MALLOC, DBG_SR_MEMORY, USE_FUTEX, FAST_LOCK-ADAPTIVE_WAIT, USE_DNS_CACHE, USE_DNS_FAILOVER, USE_NAPTR, USE_DST_BLACKLIST, HAVE_RESOLV_RES ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144, MAX_LISTEN 16, MAX_URI_SIZE 1024, BUF_SIZE 65535, DEFAULT PKG_SIZE 8MB poll method support: poll, epoll_lt, epoll_et, sigio_rt, select. id: 892ad6 compiled on 14:33:45 Apr 18 2018 with gcc 4.8.5 [root@kamailio]# rpm -qa | grep freeradius-client freeradius-client-1.1.7-16.el7.centos.x86_64 -- BR, Denys Pozniak