Problems with certificates for custom multi-level subdomains

Hi!

I’ve read the two other topics related to this but they both deal with default github-provided domain names wheres I have a custom domain. Should I be able to use multi-level subdomains in this case? Say something like blog.githubpages.organizationname.com

I’ve actually set this up for two (internal) repositories and it works fine with HTTP but neither has been able to generate a certificate. One has been stuck in 1/3 certificate creation for over 24hrs now with the message “Certificate Request Error: Certificate provisioning will retry automatically in a short period, please be patient.” while the other one just says “Something went wrong issuing a certificate for foo.bar.organization.com. Please contact the Pages team.”

Edit: looks like the second one actually now works so this feature seems to be supported, which is great. However the other one is still stuck.

Turns out there is a limit on the length of the domain name. This is apparently not documented anywhere.