Forum not working after configuring CDN (ERR_CERT_COMMON_NAME_INVALID)

I configured stackpath CDN.

I configured my DNS with the provided info:

A @ 300
CNAME www 300

I edited app.yml and rebuilt the app:


But now the forum won’t load: NET::ERR_CERT_COMMON_NAME_INVALID

Any idea? :frowning:

edit: my CDN settings:

re edit: uuuh, now that’s a 503 error :thinking:

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So what is the forum domain?

Shouldn’t you use




Your CDN URL is your Site’s Edge Address at Stackpath, which as @falco noted is top-right in your screenshot.

You’ve specified the site URL as the CDN URL, leaving the site referring to… itself? Like some bizarre CDNipede :bug:


Hi, thank you, I fixed my appl.yml. :+1:

The error 503 is gone, but I’ve still the SSL issue :thinking:

Here are the SSL settings in my stackpath panel, I don’t know if it’s of any usefulness:

This server couldn't prove that it's;
its security certificate is from *

So you have a VPS running on, a DNS entry for of type A pointing to and your app.yml hostname is set to ?

So you will need to “create an additional certificate to use with custom Delivery Domains” using that blue button in the middle.


Well, I’m a bit lost (and reply precisely to your question at the end of the message)

I followed this #howto:

  1. The CNAME , which is the “friendly” name for your CDN that you’ll set up in your DNS, e.g.
  2. The CDN URL , which is the “unfriendly” name for where the cached CDN assets will be coming from via the CDN’s worldwide network of distributed servers. It will look like

Stackpath told me to add this in my DNS (the screenshot is from my stackpath configuration steps):

The CNAME entry being www, I assumed that the “friendly” name for my CDN would be

Then, still following the #howto where the “friendly” name is added to the app.yml:

Uncomment the CDN line in your app.yml and update it with the CNAME you just set up in your DNS:

## the origin pull CDN address for this Discourse instance

I did the same and I set DISCOURSE_CDN_URL to

So I don’t quite understand why I should set the “unfriendly” name in my app.yml when the #howto tell me the opposite.

As for the IP and domains:

My VPS IP is
The A entry that I added following stackpath’s configuration steps is their own IP (as I understand it).
My app.yml hostname is

Oh, I’ll have a look at this!

Yup: that was that. Thanks guys!

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