radiusd service start timeout

[Alan Smith]

Hi all,
I am using freeradius 3.0.20 with MariaDB. Radius clients are stored in the database. 
When I try to start the service, it will attempt to start the service. Then 1 minute 30 seconds later, it will log error message timed out.In /var/log/radius/radius.log, I can check the clients are still being loaded (not completed yet).The output of systemctl status radiusd is as follows.

  Oct 24 15:17:19 servername systemd[1]: Starting FreeRADIUS high performance RADIUS server....Oct 24 15:18:49 servername systemd[1]: radiusd.service start-pre operation timed out. Terminating.Oct 24 15:18:49 servername systemd[1]: radiusd.service Failed with result 'timeout'.Oct 24 15:18:49 servername systemd[1]: Failed to start FreeRADIUS high performance RADIUS server..
May I know how this can be fixed? Thank you in advance.