VideoCall Establishment Getting delay

Hi,
I have deployed 2.13.0 openvidu server in ubuntu . every thing working fine if there is internet connection in server. if there is internet connection in server video call is established between 2 to 3 sec. but if internet connection is not present in server video call establishment is taking 15 to 20 sec.
I can not able to find out what’s happening.
Please anyone help me to solve this.
Any help is appreciated!
Thanks.

Please, update your OpenVidu deployment to last version (2.15.0) and try again