You may see the following error in the message log after a failure to start named.
isc_stdio_open '/var/log/named/named.log' failed: file not found
This is caused by the named log not existing at /var/log/named/named.log.
1) Create the directory if it doesn't exists already.
2) Create the log file.
3) Change the ownership of the file.
chown named: /var/log/named/named.log
4) Start named.