I'm opening (using OpenUrl) an external webpage I control. During loading of this web page, from the server I wish to close the teams modal either directly, or by invoking the teams client to resend message with a parameter, so the bot can respond with a close response (which I have working).
I'm able to do other tasks from an external service, like posting messages to existing or new chats. But when I try to set the activity type to invoke, I get BadRequest response.