Multiple answers can be found on the internet:
Another weather-program using FTP upload runs into the same error
http://discourse.weather-watch.com/t/70699
Seems the provider change the folder structure for uploads.
Solution was found when first testing manually upload.
Also http://discourse.weather-watch.com/p/563791
Same problem on a Belgian site
FTP an SFTP upload use different start-folders.
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https://bobcares.com/blog/ftp-550-no-such-file-or-directory/
- Incorrect path
Usually, “FTP 550 no such file or directory” error happens when the customers try to upload files from the wrong directory.
For example, when the file is present in the folder /home/user/abc.html, an attempt to upload from the path /home will cause this error.
This error also happens when customer uses the relative path in FTP.