Hi, Anyone knows what could be wrong? This happens only when the client using TCP sending registration. First, there are a LOT of following lines: Oct 2 16:26:52 ip67-153-142-69 /usr/local/sbin/openser[2463]: ERROR: build_res_buf_from_sip_req: out of memory ; needs 698 Oct 2 16:26:52 ip67-153-142-69 /usr/local/sbin/openser[2463]: challenge(): Error while sending response Oct 2 16:26:52 ip67-153-142-69 /usr/local/sbin/openser[2463]: ERROR: build_res_buf_from_sip_req: out of memory ; needs 698 Oct 2 16:26:52 ip67-153-142-69 /usr/local/sbin/openser[2463]: challenge(): Error while sending response Then, following: Oct 2 16:30:09 ip67-153-142-69 /usr/local/sbin/openser[2462]: ERROR: build_res_buf_from_sip_req: out of memory ; needs 779 Oct 2 16:30:09 ip67-153-142-69 /usr/local/sbin/openser[2462]: challenge(): Error while sending response Oct 2 16:30:09 ip67-153-142-69 /usr/local/sbin/openser[2462]: ERROR: build_res_buf_from_sip_req: out of memory ; needs 779 Oct 2 16:30:09 ip67-153-142-69 /usr/local/sbin/openser[2462]: challenge(): Error while sending response Then, Oct 2 16:49:01 ip67-153-142-69 /usr/local/sbin/openser[2462]: ERROR: build_res_buf_from_sip_req: out of memory ; needs 780 Oct 2 16:49:01 ip67-153-142-69 /usr/local/sbin/openser[2462]: challenge(): Error while sending response Oct 2 16:49:41 ip67-153-142-69 /usr/local/sbin/openser[2462]: ERROR: build_res_buf_from_sip_req: out of memory ; needs 780 Oct 2 16:49:41 ip67-153-142-69 /usr/local/sbin/openser[2462]: challenge(): Error while sending response And on and on. Using UDP register are fine. Thanks in advance:-). Best Regards, Bill