If you are getting the error below:
systemd: firewalld.service: Start operation timed out. Terminating.
systemd: Failed to start firewalld – dynamic firewall daemon.
It may be due to the fact that the process is stuck somehow. Just run the following command to solve the issue:
Terminate the process
pkill -f firewalld
firewall-cmd --state systemctl start firewalld firewall-cmd --state