Yealink T49G video call problem on asterisk?

I have two Yealink T49G sip video phones. They are connected to Asterisk system.
Audio negotiation is ok but they can not send video negotiation eachother. What can be reason?

I have tried same scenario with two Grandstream GXV3275 video phones and they worked fine in audio and video negotiation.
By the way my asterisk version is: Asterisk 13.6.0

I’d suggest trying the latest version to ensure that you have the latest core and SDP fixes. If after that it still occurs then provide the configuration and console output with SIP traffic (sip set debug on or pjsip set logger on depending on channel driver in use).