A way to stop lftp from issuing "CWD /" when transferring a file

Question

Given an lftp command similar to the following:

lftp -vv -d -c set ssl:ca-file /path/to/cert/ftps_cron-bundle.crt; set ssl:check-hostname no; set ftp:ssl-protect-data true; set sftp:connect-program "ssh -a -x -o PubkeyAuthentication=no"; set net:max-retries 2; open -e 'put /path/to/data/upload.txt;' -u username:password ftps://server.example.net/

The command template works on various servers, but, on one server, even though the upload is successful, an error message is shown:

---- CWD path to be sent is `/'
<--- 200 Command OPTS succeed
---> CWD /
<--- 550 Permission denied
cd: Access failed: 550 Permission denied (/)

How does one prevent lftp from sending CWD / to this server?

<--- 230 User logged in
---> FEAT
<--- 211-Extensions supported
<---     SIZE
<---     XMD5
<---     XSHA1
<---     XSHA256
<---     XSHA512
<---     XQUOTA
<---     LANG EN, ES, FR, GE
<---     MDTM
<---     MLST size*;type*;perm*;create*;modify*;
<---     REST STREAM
<---     TVFS
<---     UTF8
<---     AUTH SSL;TLS-P;
<---     PBSZ
<---     PROT C;P;
<--- 211 end
---> PWD
<--- 257 "/username/folder" is current directory
---> PBSZ 0
<--- 200 PBSZ=0
---> PROT P
<--- 200 PRIVATE data channel protection level set
---> LANG
<--- 200 Default languages set to EN
---> OPTS UTF8 ON
<--- 200 Command OPTS succeed
---> OPTS MLST size;type;perm;modify;
---- CWD path to be sent is `/'

Note that the server automatically sets its default upload directory based on the username... i.e. /username/folder

The upload should go to this default upload directory without generating an error message. It does get uploaded, but the log shows the error message:

cd: Access failed: 550 Permission denied (/)
---> TYPE I
<--- 200 Transfer mode set to BINARY
---> PASV
<--- 227 Entering Passive Mode (10,10,35,21,195,225).
---- Address returned by PASV seemed to be incorrect and has been fixed
---- Connecting data socket to (nnn.nnn.nnn.nnn) port 50145
---- Data connection established
---> ALLO 148891
<--- 200 Command ALLO succeed
---> STOR upload.txt
<--- 150 Uploading in BINARY file upload.txt
Certificate: ...
Issued by: ...
Trusted
WARNING: Certificate verification: hostname checking disabled
---- Closing data socket
<--- 226 Transfer completed
---> SITE UTIME 20190819100016 upload.txt
<--- 550 Command SITE failed
---> QUIT
---- Closing control socket

A number of things have been tried. For example, using various paths with the put command.

• put -O . /path/to/data/upload.txt
• put -O /username/folder /path/to/data/upload.txt

Explicitly placing a cd /username/folder command was also attempted.

Removing -vv and -d are ineffective as well.

How can lftp be made to avoid automatically issuing the CWD / that causes the unwanted and confusing error message that does not actually mean anything failed?

$ lftp --version
LFTP | Version 4.4.8 | Copyright (c) 1996-2013 Alexander V. Lukyanov
...
Libraries used: Readline 6.2

Answer 1

Either append a tilde (~) to the end of the URL:

ftps://server.example.net/~

or, simply drop the trailing slash:

ftps://server.example.net