Slot available after booking

I would expect the slot to be blocked if someone already booked that slot. When I was testing I could pick the same slot even after confirmation.

I read in the forum about setting up cron job. Is setting up a cron job is the only way to clear out the slots that have been taken. My hosting provider does not allow wget. I have never set up a cron job before so want to make sure I have it correctly. Following is what I did.

I created a php file with the following content:

<?php

/** 
* This cron runs every n minutes to clear the reserved slots in the scheduling calendar
*
*/

_ea-action=clear_reservations > /dev/null 2>&1

And in the cPanel they have option to set up the cron so there I entered the following. (I wanted to insert a screenshot here but not sure how to do that, don’t see an option for that and copy paste is not working)

Min Hour Day Month Weekday command
*/5 * * * * php -q /usr/local/bin/ea-php56 /home/<username>/public_html/wp-admin/Crons/clearschedule.php

Please let me know whether I have the cron job set up correctly.

Thanks