Intermittent SFTP issue for outbound interface

Hi all,

All the outbound interfaces in Production use SFTP (Linux) to transfer files to feeder systems.

However, occassionally,  the SFTP program fails to establish a connection:

Connecting to host xx.xxx.xxx.xxx.......

Connection closed

Also, what is strange is that it happens only for that particular file for which it failed.

For example, file1 is created by the interface code and SFTP concurrent program is called and SFTP fails with above error.

Then file2 is created in the next run of the interface and SFTP works fine.

If after this we try re-sending file1 through SFTP it fails again!