Save the old Falcon configuation and add symlink from /etc/falcon/conf:

mv /etc/falcon/conf /etc/falcon/conf.saved

ln -s /usr/hdp/current/falcon-client/conf /etc/falcon/conf

ls -la /etc/falcon

total 4
drwxr-xr-x 3 root root 4096 Jun 19 21:51 2.3.0.0-2323
lrwxrwxrwx 1 root root   35 Jun 19 21:54 conf -> /usr/hdp/current/falcon-client/conf
drwxr-xr-x 2 root root 4096 Jun 14 00:11 conf.saved

From Ambari Web, browse to Services > Falcon.

From the Service Actions menu, select Start.

After Falcon has started, select Run Service Check. Confirm the Check passes.