FTP instantiation fails due to PWD error

My RedHat machine (R2022b) cannot open ftp connections (including the example in matlab documentation). The error I get is:

Error using matlab.io.ftp.FTP

An internal error occurred during FTP operation "PWD": Could not match any server responses to the PWD command: HTTP/1.1 501 method notimplemented

Content-Type: text/html

Cache-Control: no-cache

X-Frame-Options: deny

Proxy-Connection: Keep-Alive

I haven't been able find any reference to this. This seems to indicate my client couldn't handle what came back from the server. It isn't the server (ftp.avl.class.noaa.gov) because I can connect using other machines / platforms / matlab version. Any ideas what could cause this? I believe matlab supplies its own ftp client.

I see a few class definitions in:

toolbox/matlab/io/ftp/+matlab/+io/@FTP

toolbox/matlab/io/ftp/+matlab/+io/+ftp/@FTP

In another machine (R2018b which works) I see a different toolbox organization:

toolbox/matlab/iofun/@ftp/ftp.m,

so the organization of the FTP interface has evolved in the last few years.

[Walter Roberson]

On my Mac, R2021a, R2021b, R2022b, R2023b, the function is at toolbox/matlab/io/ftp/ftp.m

I do see directories such as matlab/io/ftp/+matlab/+io/+internal/+ftp/@FTP

But I do not see any @ftp directory.

[SA]

Thanks for the reference. I just installed 2023a and the toolbox structure matches what you list, however I get the same error. The matlab ftp client must have a dependency that is incompatible on my machine.

It looks like ftp.m tests for a feature "FTPV2" and then if this exists, uses matlab.io.ftp.FTP, and if the feature is absent, uses matlab.io.internal.ftp.FTP. On my errant machine, the feature exists, so it is using the former class. I think I have found the problem. I'll have to dig some more to fix it.

[SA]

The error above from toolbox/matlab/io/ftp/ftp.m is generated before any connection to a server is attempted. If anyone runs into this issue, my work around is to replace calls to ftp() with matlab.io.internal.ftp.FTP().