Plesk unavailable - Error while upgrading from Ubuntu 14 to Ubuntu 16

2:~# /opt/psa/bin/distupgrade.helper.ubt14-ubt16_post.x64.sh
Bootstrapper repair actions failed
Some error during dist-upgrade post stage have occurred.
Check /var/log/plesk/install/plesk-distupgrade.log for error details.
Visit https://docs.plesk.com/en-US/current/administrator-guide/server-administration/distupgrade-support.74627/ for information about troubleshooting and recovering from failed dist-upgrade.

2:~# tail...