unable to start cobrowse session

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We're trialling basic cobrowse capability during a chat session within CP.  I have followed the user guide to create workspace and placed the cobrowse premium weidget onto the chat_landing.php page. However, after agent initiated the screen sharing request during a chat session and customer accepted it, then it seen to be stucked at 'Initializing and connecting screen-sharing session...'

I'm logging in both the agent desktop and CP from the same PC, not sure if this caused the issue?

any advise is highly appreciated.