donkiely on "[Plugin: Simple Calendar - Google Calendar Plugin] Calendar Events Don't Appear"

I'm trying out Simple Calendar on a club Web site. I made use of the documentation and the WPbeginner post about configuring the calendar and plugin, so I think I've configured the calendar correctly. We've used the embedded iframe code from Google for a couple of years now, so the calendar is publicly shared. I've triple-checked that I've set the correct API in Simple Calendar's settings, as well as the Calendar ID in the new calendar. Yet only the empty calendar appears.

Here is a test page on our development site:
http://rcn-wp.donkiely.net/testcalendar/

And here is the embedded calendar iframe linked to the same calendar, which is working fine:
http://rcn-wp.donkiely.net/calendar/

As you can see, we have at least a couple of events every week. Yet nothing shows up on the Simple Calendar version of the page.

Below is the system report text. Shortcode I'm using is [calendar id="416"]. I'm using Divi with a child theme, and I've verified that wp_footer() is in footer.php.

What might I be doing wrong?

Thanks!
Don

System Report:

### WordPress Installation ###

Site Name: Running Club North
Home URL: http://rcn-wp.donkiely.net
Site URL: http://rcn-wp.donkiely.net
Version: 4.4.2
Locale: en_US
Timezone: America/Anchorage
Multisite: No
Permalinks: /%year%/%monthnum%/%postname%/
WP Memory Limit: 40 MB
WP Debug Mode: No
Script Debug: No

### Active Theme ###

Theme: Divi Child Theme - 1.0.1
Child Theme: Yes
Parent Theme: Divi - 2.6.4.4

### Active Plugins ###

Better Plugins Plugin: 1.0.1
Yoast SEO: 3.1.2
Google Analytics by Yoast: 5.4.6
WP Crontrol: 1.3
TablePress: 1.7
Simple Calendar: 3.0.16
ManageWP - Worker: 4.1.30
Post Snippets: 2.5.3
Gravity PDF: 3.7.6
WPS Hide Login: 1.1.5
Wordfence Security: 6.0.25
WooCommerce: 2.5.5
WP Notification Center: 1.0.0
Gravity Forms: 1.9.18
Lightbox Plus Colorbox: 2.7.2
Post Expirator: 2.1.4
Jetpack by WordPress.com: 3.9.6
Elegant Themes Updater: 1.2
Akismet: 3.1.10

### Server Environment ###

Web Server: Apache
PHP Version: 5.6.17
MySQL Version: 5.5.42-37.1-log
Server Timezone: UTC
Display Errors: No
Safe Mode: No
Memory Limit: 256M
Upload Max Filesize: 10M
Post Max Size: 10M
Max Execution Time: 30
Max Input Vars: 1000
fsockopen: Yes
cURL: Yes
SOAP: Yes
SUHOSIN: No
WP Remote POST: Yes
WP Remote GET: Yes

### Client Information ###

IP Address: 69.195.124.124
Browser: Chrome 49.0.2623.110 (Windows)

https://wordpress.org/plugins/google-calendar-events/