Recently, I met the problem when I ran blockMesh
word::stripInvalid() called for word hostname localhost-01
For debug level (= 2) > 1 this is considered fatal
the problem may come from postfix mail service. when checked your postfix, it output
valid_hostname: invalid character 32(decimal): localhost-01
postfix: fatal: unable to use my own hostname localhost-01
The reason was that there's a space, which value is 32 in ASCII in decimal. The problem was caused by postfix.
the solution was to edit /etc/postfix/main.cf. Uncomment the line with your hostname like this
myhostname=localhost-01
Without any special character or space before or after the hostname "localhost-01".
Then it was success without error.
sudo systemctl restart postfix.service
Then restart the computer. It works.
NOTICE
it may not work every time. I cannot reproduce the error.