While working with FTP you may encounter the error “550 Permission denied" or "550 Operation not permitted", Which indicates the lack of rights to perform the transaction.
This problem occurs due to the download of files (most often commands
APPE) to hosting within the user for which the mode is set only for reading... To fix the error, you should either use another FTP-user or disable mode only for reading.
If an error occurs when trying to write to a directory
etclocated in the root access directory by FTP, then its reason is that writing to these directories, if they are located at the root, is prohibited by the settings FTP (source). Decision -change access directory so that directories
etc in the end were not at the root.