There was no sound on the sipML5

Hello everyone,I have a sound problem with WebRTC
Now,I can login simpl5 and can call extension,but There was no sound on the sipML5,I use asterisk 15.5

This is error massage:
ERROR[4201]: pjproject:0 <?>: icess0x7f7838020458 …Error sending STUN request: Invalid argument

But I didn‘t configure any about stun,Can you help me?Thank you!
If need more massage,pleaase tall me,Thank you again!

this is my configure
pjsip.conf
[600]
type=aor
max_contacts=5
remove_existing=yes

[600]
type=auth
auth_type=userpass
username=600
password=600 ; This is a completely insecure password! Do NOT expose this
; system to the Internet without utilizing a better password.

[600]
type=endpoint
aors=600
auth=600
dtls_auto_generate_cert=yes
webrtc=yes
; Setting webrtc=yes is a shortcut for setting the following options:
; use_avpf=yes
; media_encryption=dtls
; dtls_verify=fingerprint
; dtls_setup=actpass
; ice_support=yes
; media_use_received_transport=yes
; rtcp_mux=yes
context=pjsiptext
disallow=all
allow=opus,ulaw

[602]
type=aor
max_contacts=5
remove_existing=yes

[602]
type=auth
auth_type=userpass
username=602
password=602 ; This is a completely insecure password! Do NOT expose this
; system to the Internet without utilizing a better password.

[602]
type=endpoint
aors=602
auth=602
dtls_auto_generate_cert=yes
webrtc=yes
; Setting webrtc=yes is a shortcut for setting the following options:
; use_avpf=yes
; media_encryption=dtls
; dtls_verify=fingerprint
; dtls_setup=actpass
; ice_support=yes
; media_use_received_transport=yes
; rtcp_mux=yes
context=pjsiptext
disallow=all
allow=opus,ulaw

extensions.conf
[pjsiptext]
exten => 600,1,Dial(pjsip/600)
exten => 600,2,hangup()

Have you done any investigation of the ICE/STUN or DTLS negotiations? Have you consulted the browser Javascript console to see if anything sticks out?

If you are going to use WebRTC seriously in any fashion these are things you need to learn and dig into. There are a lot of moving parts outside of Asterisk that can cause problems.

As for the “Error sending STUN request” message that is generally harmless - it usually occurs when you don’t have IPv6 but it is trying an IPv6 path.

thank you for you reply!I will be on the issues for further study .