Specifically, check the dialplan for this extension: "Calls from BoxB" or post it so we can look at it and help you, but please don't do it here, use pastebin!!: pastebin.freeswitch.org then send us the link.
I would guess there is an error in public on A, but you didn’t
include all of that context so I can’t say for sure. Note that it matches
10001 in public, but when it gets to Local_Call, it just sees $1, not 10001.
That s why the match is failing.