Summary chart never loads on overview page

The Summary and Top Referring Sites charts on the overview page never load, they just display the rotating clock graphic. Everything else seems to work. I would appreciate any help tracking this down. Trying to debug, I find the following…

PHP Version : 5.6.30

CONSOLE MESSAGES

JQMIGRATE: Migrate is installed, version 1.4.1
VM2952:1 POST https://www.bibletruths.org/wp-admin/admin-ajax.php 500 (Internal Server Error)

THE AJAX REQUEST IS…

General
Request URL:https://www.bibletruths.org/wp-admin/admin-ajax.php
Request Method:POST
Status Code:500 Internal Server Error
Remote Address:66.96.149.17:80
Referrer Policy:no-referrer-when-downgrade

Response Headers
Accept-Ranges:bytes
Access-Control-Allow-Credentials:true
Access-Control-Allow-Origin:https://www.bibletruths.org
Age:2
Cache-Control:no-cache, must-revalidate, max-age=0
Connection:keep-alive
Content-Length:519
Content-Type:text/html
Date:Tue, 10 Oct 2017 14:16:37 GMT
Expires:Wed, 11 Jan 1984 05:00:00 GMT
Last-Modified:Thu, 25 Apr 2013 22:38:40 GMT
Server:Apache/2
Set-Cookie:icwp-wpsf-flash=deleted; expires=Thu, 01-Jan-1970 00:00:01 GMT; Max-Age=0; path=/
X-Content-Type-Options:nosniff
X-Frame-Options:SAMEORIGIN
X-Powered-By:PHP/5.6.30
X-Robots-Tag:noindex

Request Headers
Accept:*/*
Accept-Encoding:gzip, deflate
Accept-Language:en-US,en;q=0.8
Connection:keep-alive
Content-Length:55
Content-Type:application/x-www-form-urlencoded; charset=UTF-8
Cookie:wordpress_4f6d5efd2e65f0a7a539488851fe61e6=admin%7C1507675920%7CjUKmvCrukrJTDNGmekGujnN4ot2zsx79CsROQqxsfOx%7C0e8bf260be95ce5ce67bca60fae3f6190751340077ea1cee9a33c29c22a9c96d; toplevel_page_shortcodes-ultimate_last_tab=1; icwp-wpsf=4902de53880fd867e2e11a08c41622a2; wordpress_logged_in_4f6d5efd2e65f0a7a539488851fe61e6=admin%7C1507675920%7CjUKmvCrukrJTDNGmekGujnN4ot2zsx79CsROQqxsfOx%7C9ed694291d4e1964d25b8147092bd0ef5591a02e9b09fd967e8c5aa974f67eb2; redux_current_tab_get=2; _ga=amp-iU2cWjXJ_U_TyK9YiOrM-Q; redux_current_tab=6; wp-settings-1=hidetb%3D1%26editor%3Dtinymce%26libraryContent%3Dbrowse%26wplink%3D1%26align%3Dcenter%26imgsize%3Dfull%26urlbutton%3Dnone%26dfw_width%3D797%26advImgDetails%3Dshow%26ed_size%3D360%26posts_list_mode%3Dlist%26uploader%3D1%26post_dfw%3Doff%26unfold%3D1%26mfold%3Do; wp-settings-time-1=1507644329
DNT:1
Host:www.bibletruths.org
Origin:https://www.bibletruths.org
Referer:https://www.bibletruths.org/wp-admin/admin.php?page=wps_overview_page
User-Agent:Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36
X-Requested-With:XMLHttpRequest
Form Data
view source
view URL encoded
action:wp_statistics_get_widget_contents
widget:summary

THE ACTUAL TRANSACTION IS…

XMLHttpRequest.send (async)
(anonymous) @ VM2952:1
send @ load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.8.2:4
ajax @ load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.8.2:4
wp_statistics_get_widget_contents @ log.js?ver=4.8.2:14
(anonymous) @ log.js?ver=4.8.2:27
i @ load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.8.2:2
fireWith @ load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.8.2:2
y @ load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.8.2:4
c @ load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.8.2:4

The page I need help with: [log in to see the link]