FTPS File upload fails with '450 Transfer aborted. Link to file server lost'

[Warren White]

When uploading files to the server I am receiving the error '450 Transfer aborted. Link to file server lost'. Upon investigating it seems that this is a bug and has been fixed in the proftpd github: https://github.com/proftpd/proftpd/issues/959. The fix was applied to 1.3.7 and back patched to 1.3.6d.

The release notes for 1.3.6d can be found here: https://github.com/proftpd/proftpd/blob/1.3.6/RELEASE_NOTES

I am currently running Ubuntu Server 20.04.

proftpd-basic:
  Installed: 1.3.6c-2
  Candidate: 1.3.6c-2
  Version table:
 *** 1.3.6c-2 500
        500 http://archive.ubuntu.com/ubuntu focal/universe amd64 Packages
        100 /var/lib/dpkg/status

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Stephane (nuitari8)]

I've also got this problem, and the workaround in the upstream's github doesn't work because proftpd v1.3.6c doesn't actually know the TLSv1.3 configuration keyword.

Ubuntu 22.04 is also a no go because the package there is also 1.3.6c.