calling to a external party which is busy
When calling to an external party and receiving a 486/Busy here there is MS Teams notification presented at the client with the message "Sorry, we couldn't connect you". This is the same message when calling to a number which is not in use. I think it would be better to display a message with the information that the called party is busy so that the user could call at a later moment
When calling a user that is is a call and has busy options the following is displayed on a windows client: "The person you are trying to reach is busy or currently in a call. Please try again later."
When the same is tried from an iOS client the following is displayed: "The call could not be completed"
This is confusing for the user as it implies a technical issue rather than the destination being busy