Links to PDF files result in "Secure Connection Failed"


Here is an example of the problem I have encountered:

On this page of my WordPress website, hosted by SiteGround:

In a sentence that begins, “UPDATE: I uploaded an 92-page WHITE PAPER…”, “WHITE PAPER” is hyperlinked to

When I click that link, I receive these error messages:

This site can’t be reached. unexpectedly closed the connection.

Secure Connection Failed. The connection to was interrupted while the page was loading. The page you are trying to view cannot be shown because the authenticity of the received data could not be verified. Please contact the website owners to inform them of this problem.

This site can’t be reached. unexpectedly closed the connection. Try:
Checking the connection
Checking the proxy and the firewall
Running Windows Network Diagnostics

All browsers are updated regular and all are most recent version. I cleared cache for each browser.

I have used the WordPress plugin SSL Insecure Content Fixer for more than a year without a problem. Nonetheless I tried accessing uploaded PDF files with that plugin deactivated, but it did not make a difference.

I did search the forum for similar topics. I have read “How do I fix the SSL Mixed Content Error Message?”

I open to any suggestions!

Many thanks - Mark

P.S. I uploaded images of my Cloudflare settings–both from within SiteGround and on, and I copied-and-pasted other possibly relevant info below. I admit to being in over my head with a lot of this, but I am trying to learn.

Operating System: Linux
Server: Apache
Memory usage: 11.87 MByte
MYSQL Version: 5.6.36-82.1-log
PHP Version: 7.0.26
PHP Allow URL fopen: On
PHP Memory Limit: 768M
PHP Max Upload Size: 128M
PHP Max Post Size: 128M
PHP Max Script Execute Time: 120
PHP Exif support: Yes ( V7.0.)
PHP IPTC support: Yes
PHP XML support: Yes
Site URL:
Home URL:
WordPress Version: 4.9.1
WordPress DB Version: 38590
Multisite: No
Active Theme: eleven40 Pro Theme 2.2.1
Site Title:
Site Language: en-US
Front Page Displays: posts
Search Engine Visibility: 1
Permalink Setting: /%postname%/

Active Plugins

Accelerated Mobile Pages: 0.9.71
Akismet Anti-Spam: 4.0.2
All In One SEO Pack Pro: 2.5.3
EWWW Image Optimizer Cloud: 4.0.6
Genesis Design Palette Pro: 1.3.22
Genesis Design Palette Pro - Entry Content: 1.0.4
Genesis Simple Edits: 2.2.0
Google Analytics Dashboard for WP (GADWP):
JCH Optimize Pro: 2.2.1
Redirection: 2.10.1
Sassy Social Share: 3.1.6
SBI! for WP: 1.7.6
SG Optimizer: 3.3.5
Simple Social Icons: 2.0.1
SSL Insecure Content Fixer: 2.5.0
TinyMCE Advanced: 4.6.7
Wordfence Security: 6.3.22
WP Broken Link Status Checker: 1.0.4


I forgot this image:


You should link directly to your host name, not the CNAME target. So instead of it should be


Thank you.

Yeah, I did not create that cloudflare link and I’m not sure how it got there. Oh well, I’ll hope it was a one-time glitch. :gear:


Might be coming from code editor?
We mistake Cloudflare cached URLs code source in our web editing tools.

They appear in Googles Webmaster Tools as 404 errors
“/CDN-CGI/cf” or something similar.
Created by copying and pasting source code hurrying a project,
no one to blame but ourselves.

PhpStorm hints when I have an external resource in edit mode.
Our team uses Dreamweaver (DW) to manage Adobe Bridge and Lightroom local assets.

DW > code view > the top panel > displays associated page assets, Php, CSS, JS, etc…
It will pull canonical linked cached pages from Cloudflare display that in source view and can be mistaken as part of our working project.

DW has an external source hinting, but we ignore it which is our fault.


Thank you 6xbytes - I don’t use a code editor, but every clue helps!


What is baffling about this problem is that the HTML I see within the Wordpress admin panel is correct:

But on the live site, “” has mysteriously been added to the URL:

If anyone has suggestions, I am open to new ideas. :O)


Thanks to some excellent advice from CloudFlare Support, I was able to resolve the problem.

I deactivated all plugins and then started reactivating them one-at-a-time. I discovered the problem: A setting within JCH Optimize Pro (which has been a great plugin for me, with very good support, so I’d put this under the category of “user error”, i.e., I just did not know enough to get the setting right.)

JCH Optimize Pro Settings > Pro Features > CDN/Cookieless Domain - I needed to unclick (deselect) PDF files. When I did that the problem went away. :O)

I also unclicked Word doc files, just in case.


Thank you everyone for your help. :O)


The way this issue has figured out for you is confusing to me a little because I have exactly the same (with all these error logs in different browsers) but I had the PDF’s unclicked and it led me to nothing. I thought it was a WP and I set it up wrong in some way but it appeared that the deal was with the documents themselves. After I’ve uploaded them one by one to this editor saved as new files and linked on the website again, everything started to work as it supposed to again