"CNAME is already taken" error for .fish domain. Maybe an edge case bug?

I have the domain lo.fish.

Tried to set it up as the custom domain for my github page but got the following error instead:

The CNAME lo.fish is already taken. Check out https://docs.github.com/articles/troubleshooting-custom-domains#cname-errors for more information.

Look through all my repos and don’t see it being used.

Doubt someone is actually trying to use this domain.

Maybe a werid bug for speical cases?

Couldn’t remember if I have used it previously. Could be a cache thing too.

Would be nice if I can use my domain asap. Thanks!

this is the repo for the gh pages: https://github.com/CAST3LLA/lo.fish/

Thanks for reaching out!

Due to the sensitive nature of your request, we have escalated this to a ticket in our private support tracking system and we will be following up with you via that mechanism shortly. Additionally, to prevent accidental sharing of private information, we are closing this topic. Thanks very much for your patience!

Cheers!