Kubuntu 18.10 updates FileZilla from the version 3.28.0 to the version 3.33.0. Since the update TLS encrypted connections fail with this error message:
Erreur GnuTLS -50 dans gnutls_priority_set_direct: The request is invalid.
Kubuntu 18.10 updates FileZilla from the version 3.28.0 to the version 3.33.0. Since the update TLS encrypted connections fail with this error message:
Erreur GnuTLS -50 dans gnutls_priority_set_direct: The request is invalid.
A similar issue is solved with newer versions of FileZilla. And luckily they fix my issue as well. Unfortunately at the moment the version 3.33.0 seems to be the newest version available as a Debian package. Instead you can use the build of the newest version provided directly by the FileZilla project. The installation only consists of unpacking the archive. FileZilla version 3.38.0 with GnuTLS version 3.5.19 (included in the archive) worked well for me.
UPDATE: Kubuntu 19.04 updates FileZilla from the version 3.33.0 to the version 3.39.0. Updating to Kubuntu 19.04 directly solves the issue.