Public bug reported: 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 ** Affects: proftpd-dfsg (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1917045 Title: FTPS File upload fails with '450 Transfer aborted. Link to file server lost' To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/proftpd-dfsg/+bug/1917045/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs