2.5.2.4.4. Error 550 Permission denied

The errors "550 Permission denied" and "550 Operation not allowed" usually indicate that there are not enough permissions to perform an operation.

The problem occurs when uploading files (most often STOR, RMD, APPE commands) to a hosting under an FTP user with read-only privileges. The solution is to disable read-only or use a different FTP user.

If an error occurs when trying to write to the lib or etc directory located in the root FTP access directory, the reason is that writing to these directories, if they are located in the root, is prohibited by FTP settings (source). The solution is to edit the access directory so that the lib and etc directories end up not in the root.