Trying to register PJSIP extension over TLS and SRTP

currently the output of the pjsip show transport 0.0.0.0-tls is:

 Transport:  <TransportId........>  <Type>  <cos>  <tos>  <BindAddress....................>
 ==========================================================================================
 
 Transport:  0.0.0.0-tls               tls      3     96  0.0.0.0:5061
 
 ParameterName              : ParameterValue
 =================================================================
 allow_reload               : true
 async_operations           : 1
 bind                       : 0.0.0.0:5061
 ca_list_file               : /etc/pki/tls/certs/ca-bundle.crt
 ca_list_path               : 
 cert_file                  : /etc/asterisk/keys/domain.pem
 cipher                     : 
 cos                        : 3
 domain                     : 
 external_media_address     : freepbx_IP
 external_signaling_address : freepbx_IP
 external_signaling_port    : 0
 local_net                  : 
 method                     : tlsv1
 password                   : 
 priv_key_file              : /etc/asterisk/keys/domain.key
 protocol                   : tls
 require_client_cert        : No
 symmetric_transport        : false
 tos                        : 96
 verify_client              : No
 verify_server              : No
 websocket_write_timeout    : 100

The /etc/asterisk/keys/domain.pem file looks like:

 -----BEGIN PRIVATE KEY-----
 some text
 -----END PRIVATE KEY-----
 -----BEGIN CERTIFICATE-----
 some text
 -----END CERTIFICATE-----

Few changes that I tested

  1. I deleted all certificates other than the third party one
  2. I removed local_net (not sure if it makes a difference)
  3. I used softphone app

Polycom phone is still not registering as tls

I have been looking at Yealink / Freepbx / SIP / TLS and I will try to import the server (ca.crt?) and client certificates (domain.pem?) to the Polycom phone
Is /etc/asterisk/keys/domain.pem a client certificate?