Failed to create session

I’m a chinese novice programmer.I wanna study and develop a video chat software.so I download Vidtok Free Video Chat Plugin for WordPress.but when I click on the button 1:1 video chat. then the exception is occured.” Uncaught exception ‘OpenTokException’ with message ‘Failed to create session: Invalid response from server’ in D:\wamp\www\wordpress\wp-content\plugins\vidtok-video-chat-using-tokboxs-api\libs\opentok-sdk\OpenTokSDK.php:114 Stack trace: #0 D:\wamp\www\wordpress\wp-content\plugins\vidtok-video-chat-using-tokboxs-api\vidtok-package\actions\create.php(22): OpenTokSDK->createSession(‘192.168.1.101’) #1 {main} thrown in D:\wamp\www\wordpress\wp-content\plugins\vidtok-video-chat-using-tokboxs-api\libs\opentok-sdk\OpenTokSDK.php on line 114 “
so I hope get the help from here!
sincerely