Seems like these are this is the relevant information
Running newaliases
newaliases: warning: valid_hostname: numeric hostname: 0000
newaliases: fatal: file /etc/postfix/main.cf: parameter myhostname: bad
parameter value: 0000
dpkg: error processing postfix (--configure):
subprocess post-installation script returned error exit status 75
What's your computers hostname? What does the command "hostname" output?
How does your /etc/hosts look?
** Changed in: postfix (Ubuntu)
Status: New => Incomplete
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bug fixes,security updates fail to install
https://bugs.launchpad.net/bugs/371816
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