TLS Error message?

I am trying to use TLS facility on Asterisk. When TLS client(ip phone) tries to register Asterisk Server so Asterisk gives me this error logs

[2017-07-25 16:19:24] ERROR[10202]: chan_sip.c:17770 register_verify: ‘TLS’ is not a valid transport for ‘508’. we only use ‘UDP,TCP’! ending call.
[2017-07-25 16:19:24] NOTICE[10202]: chan_sip.c:28627 handle_request_register: Registration from ‘“508” sip:[email protected]:5062’ failed for ‘’ - Device not configured to use this transport type

What can be reason?

sorry if this is to simple an answer, but did you configure the extension for tls? in the advanced tab of the extension, you need to have the transport either ‘auto’ or the tls interface. in addition, you probably want to configure srtp as well.

these 2 screen shots are from the advanced tab of an extension

finally, make sure you have the transport enabled in pjsip (or chan_sip), go to sip settings and make sure that tls is enabled on the right interface and that a port is assigned