Cannot start bind on Ubuntu: Start operation timed out. Terminating

Symptoms

Unable to start the bind9 service:

# systemctl status bind9.service
● bind9.service - BIND Domain Name Server
Loaded: loaded (/lib/systemd/system/bind9.service; enabled; vendor preset: enabled)
Active: failed (Result: timeout) since Fri 2021-01-29 10:16:18 CET; 2min 36s ago
Docs: man:named(8)
Process: 9926 ExecStart=/usr/sbin/named $OPTIONS (code=exited, status=0/SUCCESS)
...
Jan 29 10:16:18 org-www.clicksports.de systemd[1]: bind9.service: Failed with result 'timeout'.
Jan 29 10:16:18 org-www.clicksports.de systemd[1]: Failed to start BIND Domain Name Server.

Cause

Custom bind configuration.

Resolution

1. Connect to the server via SSH

2. Open the file /etc/default/bind9 (or /etc/default/named) in a text editor and change its content from:

   OPTIONS="-f -t /var/named/run-root -c /etc/named.conf -u bind -n 2"

   to

   OPTIONS=" -t /var/named/run-root -c /etc/named.conf -u bind -n 2"

3. Move the file /etc/systemd/system/bind9.service to a different directory:

   # mv /etc/systemd/system/bind9.service /root

4. Reload the daemon:

   # systemctl daemon-reload

5. Restart the bind9 service:

   # systemctl restart bind9