[Serusers]Called phone continues ringing when caller hang up (newbie)

Hi, I'm running ser-0.8.11 on a Gentoobox. When phone1 calls phone2 and hangs up when phone2 is ringing phone2 doesn't stop ringing. If the person who haves phone2 answers before it stops ringing, the conversation continues with no problem. The two phones are Zyxel P2000W. Do you see what is the problem? Thanks, Alexandre My ser.cfg : debug=3 fork=no listen=192.168.1.36 log_stderror=yes check_via=no dns=no rev_dns=no port=5082 fifo="/tmp/ser_fifo" loadmodule "/usr/lib/ser/modules/sl.so" loadmodule "/usr/lib/ser/modules/tm.so" loadmodule "/usr/lib/ser/modules/rr.so" loadmodule "/usr/lib/ser/modules/maxfwd.so" loadmodule "/usr/lib/ser/modules/usrloc.so" loadmodule "/usr/lib/ser/modules/registrar.so" modparam("usrloc", "db_mode", 0) modparam("rr", "enable_full_lr", 1) # ------------------------- request routing logic ------------------- # main routing logic route{ if (method=="REGISTER") { save("location"); break; }; if (method=="INVITE") { if (uri =~ "sip:1003@*") { forward(192.168.1.35, 5060); break; }; if (uri =~ "sip:1004@*") { forward(192.168.1.37, 5060); break; }; }; }