Do you have any chance to check the log files of the SFTP server? That might give a clear clue about the real cause of trouble.
Can you have a check on the below?
- Ensure that the user used for authentication in SFTP connection has the write permission in the remote location to create file.
- Some FTP servers, such as the one that comes default with HPUX, has option/parameter in the sshd_config that prevents setting the file permissions. Ensure that the option SftpPermitChmod is set to Yes (default).
- Increase the value of the "multiple connection" parameter
On the other hand, you may try to connect to the host where the FTP server is running and provide the real path