While trying to upload a file via FTPS, you may come across “550 supply message incomplete” error. In my case, the file upload was working fine via FTP. However, FTPS didn’t work for any IIS server and any FTP client.
Here is the entire error message:
550 supply message incomplete, signature was not verified
2019-06-13 20:28:26 184.108.40.206 SERVER\user 220.127.116.11 21 STOR test.txt 550 2148074264 0 05edb0d4-756e-4509-8d5e-4f566cae5bfb /test.txt