Attempting to send a file fbetween two CFT Monitor.
The diagnostic message is,
Remote Diagnostic Code: 904
Description: Open mode not authorized

The CFT log shows

Error
CFTT01E  CFT PART=SLIUSB04 IDF=DEFAULT IDT=D1019115 _ Open mode not allowed

And the CFTT error message is

Error message
CFTT01E: PART=&part IDF=&idf IDT=&idt _ Open mode not allowed

Explanation
A transfer request was made in OPEN mode, but this mode is not supported by the receiver partner.

Consequence
The transfer is denied. The corresponding catalog entry is set to the KEEP status.

The open mode error comes when you specify the "nfname" in the send attibutes and the receiver did not managed to allows the use of it.

For normal mode (no open mode)
= = = = = = = = = = = = = = = = = =
To send the file without using the special OPEN mode, you need to remove the value of "nfname" parameter in the sender template.

For open mode
= = = = = = = = = =
If you need to send a file using the open mode facility;  you need to specify the NFNAME it in receiver template (must be part of the FNAME field)