Error XS0032 message XProc transformation

[birstrack]

What does this error message means?
E [Add-on for Calabash XProc Engine] err:XS0032 : Input source unbound on cx:message step named !1.16 and no default binding available. (It is a static error if no connection is provided and the default readable port is undefined.)

[Mircea]

Hello,

That is an error reported by the XProc Calabash engine (https://xmlcalabash.com/) as stated here:
https://spec.xproc.org/master/head/xproc/#err.S0032

For more information we need an actual sample in order to help you.

Regards,
Mircea.