Cloudflare edge certificate import error

[superpsych0]

Checklist

• Have you pulled and found the error with jc21/nginx-proxy-manager:latest docker image?
  • Yes
• Are you sure you're not using someone else's docker image?
  • Yes
• Have you searched for similar issues (both open and closed)?
  • Yes

Describe the bug
I'm trying to import an edge certificate from Cloudflare which will cover my site.

I've done this before, it worked like a charm... then my domain name expired, and I got a new one, went through all the right steps of DNS on the Cloudflare side, and... couldn't import the edge certificate into NPM with this error:

Nginx Proxy Manager Version
v2.11.3

To Reproduce

1. Login.
2. Go to SSL Certificates.
3. Click Add SSL Certificate.
4. Click "Custom"
5. Fill in name, add key & certificate files from Cloudflare

Expected behavior
I expected the SSL certificate to be imported and used, instead of giving the error above.

Screenshots
Please see above.

Operating System
Docker container running on unRAID. Official docker image, not unRAID specific.