This is my tls.cfg for server [server:default] method = TLSv1 verify_certificate = no require_certificate = no private_key = /etc/asterisk/certs/proxy.key certificate = /etc/asterisk/certs/proxy.crt As far as I understand (verify_certificate = no), and (require_certificate = no) should allow a client connecting without certicates. Can anyone understand what this debug indicates What is causes this error tls_read_f(): TLS read:error:14094418:SSL routines:SSL3_READ_BYTES:tlsv1 alert unknown ca 7(14841) DEBUG: tls [tls_server.c:178]: tls_complete_init(): Using TLS domain TLSs<default> 7(14841) DEBUG: tls [tls_domain.c:609]: sr_ssl_ctx_info_callback(): SSL handshake started 7(14841) DEBUG: <core> [tcp_main.c:2556]: tcpconn_do_send(): tcp_send: sending... 7(14841) DEBUG: <core> [tcp_main.c:2590]: tcpconn_do_send(): tcp_send: after real write: c= 0x7eff24e41260 n=940 fd=5 7(14841) DEBUG: <core> [tcp_main.c:2591]: tcpconn_do_send(): tcp_send: buf= 
7(14841) DEBUG: <core> [io_wait.h:390]: io_watch_add(): DBG: io_watch_add(0x8df1e0, 5, 2, 0x7eff24e41260), fd_no=1 7(14841) DEBUG: tls [tls_domain.c:621]: sr_ssl_ctx_info_callback(): SSL handshake done 7(14841) DEBUG: tls [tls_domain.c:624]: sr_ssl_ctx_info_callback(): SSL disable renegotiation 7(14841) DEBUG: tls [tls_server.c:348]: tls_accept(): TLS accept successful 7(14841) DEBUG: tls [tls_server.c:355]: tls_accept(): tls_accept: new connection from 10.1.2.3:35573 using TLSv1/SSLv3 AES256-SHA 256 7(14841) DEBUG: tls [tls_server.c:358]: tls_accept(): tls_accept: local socket: 10.1.2.4:6443 7(14841) DEBUG: tls [tls_server.c:369]: tls_accept(): tls_accept: client did not present a certificate 7(14841) DEBUG: <core> [tcp_main.c:2556]: tcpconn_do_send(): tcp_send: sending... 7(14841) DEBUG: <core> [tcp_main.c:2590]: tcpconn_do_send(): tcp_send: after real write: c= 0x7eff24e41260 n=250 fd=5 7(14841) DEBUG: <core> [tcp_main.c:2591]: tcpconn_do_send(): tcp_send: buf= 
7(14841) DEBUG: <core> [tcp_read.c:296]: tcp_read_data(): EOF on 0x7eff24e41260, FD 5 7(14841) ERROR: tls [tls_server.c:1186]: tls_read_f(): TLS read:error:14094418:SSL routines:SSL3_READ_BYTES:tlsv1 alert unknown ca 7(14841) ERROR: <core> [tcp_read.c:1281]: tcp_read_req(): ERROR: tcp_read_req: error reading 7(14841) DEBUG: <core> [io_wait.h:617]: io_watch_del(): DBG: io_watch_del (0x8df1e0, 5, -1, 0x10) fd_no=2 called 7(14841) DEBUG: <core> [tcp_read.c:1437]: release_tcpconn(): releasing con 0x7eff24e41260, state -2, fd=5, id=2 7(14841) DEBUG: <core> [tcp_read.c:1438]: release_tcpconn(): extra_data 0x7eff24e3c200 10(14844) DEBUG: <core> [tcp_main.c:3385]: handle_tcp_child(): handle_tcp_child: reader response= 7eff24e41260, -2 from 1 10(14844) DEBUG: tls [tls_server.c:597]: tls_h_close(): Closing SSL connection 0x7eff24e3c200