Problems with #libidn after #Ubuntu Bionic update? One of my servers started failing 2FA, turns out libidn was misbehaving. Revert to older version: wget http://mirrors.kernel.org/ubuntu/pool/main/libi/libidn2/libidn2-0_2.0.4-1.1build2_amd64.deb && dpkg -i libidn2-0_2.0.4-1.1build2_amd64.deb && apt-mark hold libidn2-0 to workaround it :ubuntu: https://bugs.launchpad.net/ubuntu/+source/libidn2/+bug/1843507/comments/4