Hi Tech support,
 
    I just completed configuring my SER SIP Server,  I'm experiencing an intermittent error of "SIP/2.0 500 Server Internal Error" during REGISTER and whenever im using a mysql server for authentication. Most of the time, i can register successfully to the SIP Server but there are times i encounter error "SIP/2.0 500 Server Internal Error". Do you have an idea what's causing this  error.  I have here a trace log of SIP Messages.   I will greatly appreciate any support from you.
 
Thanks
Nel
 
U CLIENT-IP:1384 -> SERVER-IP:5060
  REGISTER sip:SERVER-IP SIP/2.0..Via: SIP/2.0/UDP 192.168.1.136:5060;br
  anch=z9hG4bK63235644e9b491928f5..From: 638871680007 <sip:638871680007@116.6
  8.141.251>;tag=63283ff..To: 638871680007 <sip:638871680007@SERVER-IP>.
  .Call-ID: 321f3c-24e8a-491928f0@SERVER-IP..CSeq: 6 REGISTER..Contact:
  "638871680007" <sip:638871680007@192.168.1.136:5060>..Authorization: Digest
   username="638871680007", realm="SERVER-IP", nonce="49199956fed351b86a
  5c11c83d849a62144c5dcd", uri="sip:SERVER-IP", response="6a29e5839028f9
  bc690c77fda9031054", algorithm=MD5..User-Agent: VaxSIPUserAgent/3.0..Expire
  s: 3600..Max-Forwards: 70..Content-Length: 0....
 
U SERVER-IP:5060 -> CLIENT-IP:5060
  SIP/2.0 100 Trying..Via: SIP/2.0/UDP 192.168.1.136:5060;branch=z9hG4bK63235
  644e9b491928f5;received=CLIENT-IP..From: 638871680007 <sip:638871680007
  @SERVER-IP>;tag=63283ff..To: 638871680007 <sip:638871680007@116.68.141
  .251>..Call-ID: 321f3c-24e8a-491928f0@SERVER-IP..CSeq: 6 REGISTER..Ser
  ver: Sip EXpress router (0.9.6 (x86_64/linux))..Content-Length: 0..Warning:
   392 SERVER-IP:5060 "Noisy feedback tells:  pid=16275 req_src_ip=203.1
  89.8.149 req_src_port=1384 in_uri=sip:SERVER-IP out_uri=sip:116.68.141
  .251 via_cnt==1"....
 
U SERVER-IP:5060 -> CLIENT-IP:1384
  SIP/2.0 500 Server Internal Error..Via: SIP/2.0/UDP 192.168.1.136:5060;bran
  ch=z9hG4bK63235644e9b491928f5;rport=1384;received=CLIENT-IP..From: 6388
  71680007 <sip:638871680007@SERVER-IP>;tag=63283ff..To: 638871680007 <s
  ip:638871680007@SERVER-IP>;tag=04b7610a616ee809532470b3b2dd8840.0e13..
  Call-ID: 321f3c-24e8a-491928f0@SERVER-IP..CSeq: 6 REGISTER..Server: Si