This is not a package bug, but the package correctly responding to a bad configuration in your system:
Running newaliases newaliases: warning: valid_hostname: invalid character 32(decimal): PARENTS PC newaliases: fatal: file /etc/postfix/main.cf: parameter myhostname: bad parameter value: PARENTS PC dpkg: error processing postfix (--configure): subprocess installed post-installation script returned error exit status 75
I'm converting this bug report to a support question so you can get help setting a valid hostname.
This is not a package bug, but the package correctly responding to a bad configuration in your system:
Running newaliases main.cf: parameter myhostname: bad parameter value: PARENTS PC
newaliases: warning: valid_hostname: invalid character 32(decimal): PARENTS PC
newaliases: fatal: file /etc/postfix/
dpkg: error processing postfix (--configure):
subprocess installed post-installation script returned error exit status 75
I'm converting this bug report to a support question so you can get help setting a valid hostname.