Are you using AG_FTPSYNC directly? Or
ATSYNC.LIT?
(AG_FTPSYNC is only used, as far as I know, in ATSYNC, and for that reason isn't even documented, but perhaps I passed the details on to you at some point?)
In the ATSYNC case, it reports a status code, which should give us a start. Any negative values should be those listed under the
ASHNET Status Codes Table (same as for XCALL FTP2). It should also leave behind a file %TEMP%\ashnet.log on the client machine, with the complete set of gory details.
The same should probably apply to the AG_FTPSYNC case, unless the error occurs prior to or outside the boundaries of SFTP operations.
If you give me some more details, it may help be dig up the right information (and ideally, update the docs accordingly).