I am not sure what info you derived that from.
But you should check your own info.
Perhaps take a read on this first to give you some ideas on checks you can do yourself.
The 5 most popular reasons for connection failure
The audio format is a matter of the host and is a asterisk thing you can look-up online.
The host gets to pick it in a tier of priority of preferred and available formats.
Never an issue unless there are no common formats to negotiate.
And I would still communicate with that node owner for some details before you loose to much hair on this…