Set empty value to `coturn_turn_external_ip_address_auto_detection_echoip_service_url` on main.yml

Signed-off-by: Suguru Hirahara <did🔑z6MkvVZk1A3KBApWJXv2Ju4H14ErDfRGxh8zxdXSZ4vACDg5>

group_vars/matrix_servers

@@ -3117,6 +3117,9 @@ coturn_container_image_self_build: "{{ matrix_architecture not in ['amd64', 'arm
 # to allow auto-detection (via an echoip service) to happen at runtime.
 coturn_turn_external_ip_address: "{{ ansible_host }}"
 
+# By default, we use the official public instance.
+coturn_turn_external_ip_address_auto_detection_echoip_service_url: https://ifconfig.co/json
+
 coturn_turn_static_auth_secret: "{{ ((matrix_homeserver_generic_secret_key + ':coturn.sas') | hash('sha512') | to_uuid) if coturn_authentication_method == 'auth-secret' else '' }}"
 
 coturn_lt_cred_mech_username: "{{ ((matrix_homeserver_generic_secret_key + ':coturn.user') | hash('sha512') | to_uuid) if coturn_authentication_method == 'lt-cred-mech' else '' }}"

roles/custom/matrix-coturn/defaults/main.yml

@@ -147,8 +147,8 @@ coturn_turn_external_ip_addresses: "{{ [coturn_turn_external_ip_address] if cotu
 coturn_turn_external_ip_address_auto_detection_enabled: "{{ coturn_turn_external_ip_addresses | length == 0 and coturn_turn_external_ip_address_auto_detection_echoip_service_url != '' }}"
 
 # Specifies the address of the EchoIP service (https://github.com/mpolden/echoip) to use for detecting the external IP address.
-# By default, we use the official public instance.
-coturn_turn_external_ip_address_auto_detection_echoip_service_url: https://ifconfig.co/json
+# Example: https://ifconfig.co/json
+coturn_turn_external_ip_address_auto_detection_echoip_service_url: ""
 
 # Controls whether SSL certificates will be validated when contacting the EchoIP service (coturn_turn_external_ip_address_auto_detection_echoip_service_url)
 coturn_turn_external_ip_address_auto_detection_echoip_validate_certs: true