In this document:
Introduction
Use the Time of Appointment Trigger in the notification settings to send out reminders and follow-up messages.
SMS and Emails can be setup to send at a specific time, before or after, the appointment time.
And to make sure that your messages are sending on time, we’ll also go over a handy service to help your site run its jobs on time.
Find more information on the notifications in the Email Notifications guide. Or, in the SMS notifications guide.
Reminders and Follow-Ups Using Time-Triggers
Both emails and SMS notification can turn into reminders or follow-up. Go to the notification settings and either +Add a New Notification or edit a current one.
Go down to the section that says When to Send This Notification.
Under the Trigger dropdown box, choose Time of Appointment. This will trigger based on the start time of the appointment.
The Duration, Duration Units, and When fields are specifically for the Time of Appointment Trigger.
- Duration: A number
- Duration Units: Minutes, Hours, Days, Weeks
- When: Before or After
For example, to send a reminder one day before the start of the appointment, use the settings below.

Or, to send a follow-up two weeks after the start time of the appointment, use the settings below.

Delays in Reminders
A yellow warning box could appear and show the message: This notification might be delayed or not sent as expected.
That’s because WordPress sites run and execute code/jobs when someone visits a page on your site. Instead of always checking for jobs, your site can only load when necessary. This is to avoid wasteful processing.
When a visitor goes to your homepage, WordPress loads the page and also checks for any background tasks that it should be doing. For example sending your emails.
WP-Cron is the name of the system in charge of checking for jobs.
If the system needs to send an email notification at 8AM and no one visits your site until 10AM, that means the email notification doesn’t send until 10AM.
If the appointment is at 9AM, then the notification email won’t send out, and they’ll never get that email.
How to Prevent Delays Using Uptime Robot
There’s a free service called Uptime Robot, that’ll check your website every 5 minutes and trigger WP-Cron. This will make sure your email notifications send out on time.
Set up a free account with Uptime Robot, here: https://uptimerobot.com
After signing up and logging in, you need to Add New Monitor.

Set the Monitor Type as HTTP(s). Give the Monitor a Friendly Name, such as the name of your site + Cron. And for the URL use the homepage of your site along with wp-cron.php?doing_wp_cron added to the end.
Example URL for Uptime Robot: https://mywebsite.com/wp-cron.php?doing_wp_cron

You should see the new monitor setup on the left panel, if you click on it it’ll give you more information – like when you started the monitor or if there’s any errors with it.
Related Guides
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Scheduled Event and Cron Errors
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Email Notifications
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SMS Notifications
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Reminders and Follow-Up Messages