FTP from DL360 to mainframe

[Jon Kilayko]

I am attempting to use FTP to put a FLAT file to a mainframe using MVS data sets. The FLAT file has 44 bytes with CRLF per record. The data set is configured with lrecl=256, recfm=VB and blksize=6233.

I can FTP this file if the file size is 1386 bytes or less.

If the file size is greater than 1386 bytes then the session times out after receiving the message: 125 Storing data set .

I've tried to change the lrecl, recfm and blksize settings using 'quote site' but it resulted in identical behavior.

I've successfully FTP'd this file using the same FTP account but from another physical server with the same OS.

I am a new user and apologize if this is the wrong forum or category to post this kind of message.