[Asterisk-Users] debugging trunks between two asterisk boxes at two different locations

[Sys Admin]

objective: users connected to box A can dial the extension number of
users connected to box B

boxA at location 1: works fine for internal lan users using the
firefly softphone
boxB at location 2: works fine for internal lan users using the
firefly softphone

Both the boxes have a IAX trunk defined following the instructions on:
https://sourceforge.net/docman/display_doc.php?docid=26418&group_id=121515

and guess what ...... it doesnt work ....

how do i go about debugging this thing ?

t