New to Cloudfalre: Trying to set up custom domain in Substack

I created a new domain in Cloudflare:
I want this to be my custom domain on Substack.
I followed the instructions on Substack to turn the Proxy status for CNAME to DNS only

Here is a screenshot of my dashboard in Cloudflare

Here is the error message in Substack
There’s an issue with your CNAME record
It looks like there isn’t a CNAME added to this domain. Use the above instructions for adding a CNAME for your custom domain.
There’s an issue with your A root domain record

And what I see if I try the URL
Error 1014
Ray ID: 87f4355099db2cb8 • 2024-05-05 22:36:14 UTC
CNAME Cross-User Banned
What happened?
You’ve requested a page on a website that is part of the Cloudflarenetwork. The host is configured as a CNAME across accounts on Cloudflare, which is not allowed by Cloudflare’s security policy.

What can I do?
If this is an R2 custom domain, it may still be initializing. If you have attempted to manually point a CNAME DNS record to your R2 bucket, you must do it using a custom domain. Refer to [R2’s documentation]for details.

Thanks in advance!

That means that substack hasn’t added your hostname as allowed to point to them.

It may just take a little bit of time, but you’d have to reach out to them to make sure they’ve properly got it set up for your hostnames.

Don’t forget to test both hostnames as you work your way through the issue, just to make sure they’re both getting set up correctly by substack.