The package installation process that follows time zone setting failed. Here is the first error line I found:
FAILED: apt-get -y -o Dpkg::Options::=–force-confdef -o Dpkg::Options::=–force-confnew install postfix postfix-pcre postgrey ca-certificates
The process continues and finally fails with:
After this operation, 6,368 kB of additional disk space will be used.
WARNING: The following packages cannot be authenticated!
E: There are problems and -y was used without --force-yes
The Digital Ocean vm is: 2 GB Memory / 40 GB Disk / SFO1 - Ubuntu 14.04.4 x64
Easy fix, or destroy and start over?