Dear All, Currently, we have encountered the 503 error when TLS enabled, and here is the Log: 15:52:46.820 tlsc0x1cabaa14 TLS connection closed 15:52:46.821 pjsua_app.c SIP TLS transport is disconnected from [8611766.c.talkingoa.com:9061]: Connection reset by peer [status=120054] 15:52:46.821 pjsua_app.c TLS cipher used: 0x000035/AES256-SHA 15:52:46.821 pjsua_app.c TLS cert info of [8611766.c.talkingoa.com:9061]: Version : v3 Serial : 01 3B ED Subject : *.talkingoa.com /description=riQ7Tyj49R21p0Ku/C=CN/ST=Jiangsu/L=Suzhou/O=\x00S\x00u\x00z\x00h\x00o\x00u\x00 \x00C\x00h\x00u\x00a\x00n\x00s\x00h\x00u\x00 \x00I\x00T\x00 \x00C\x00o\x00.\x00,\x00 \x00L\x00t\x00d\x00.\x00 \x00-\x00 \x82\xCF]\xDEm2\x96EO NfO\xE1`oy\xD1b\x80g\x09\x96PQlS\xF8/CN=*.talkingoa.com/emailAddress=yingyun at coperator.net Issuer : StartCom Class 2 Primary Intermediate Server CA /C=IL/O=StartCom Ltd./OU=Secure Digital Certificate Signing/CN=StartCom Class 2 Primary Intermediate Server CA Valid from : Wed 2013-02-20 00:46:47.000 GMT Valid to : Fri 2015-02-20 18:24:02.000 GMT subjectAltName extension DNS : *.talkingoa.com DNS : talkingoa.com 15:52:46.821 pjsua_app.c TLS cert verification result of [8611766.c.talkingoa.com:9061] : 15:52:46.821 pjsua_app.c - The certificate is untrusted 15:52:46.821 pjsua_app.c - The issuer info in the certificate does not match to the (candidate) issuer certificate 15:52:46.821 pjsua_app.c PJSUA is configured to ignore TLS cert verification errors 15:52:46.821 pjsua_app.c ...Call 1 is DISCONNECTED [reason=503 (Connection reset by peer)] 15:52:46.827 pjsua_app.c ... [DISCONNCTD] To: sips:1086 at 8611766.c.talkingoa.com