I’ve built a multi-tenant app and pointed a wildcard subdomain to the fly’s IP like *.example.com
This allows me to have a new subdomain for each user like first-tenant.example.com.
I’m also offering a custom domain feature in the app and using fly’s API to add new certs everytime user adds a domain in the system.
I then advise them to add a CNAME record pointing from their domain to first-tenant.example.com
Unfortunately, this doesn’t work and I have no idea why. It only works if I give them the fly’s IP address to set as A record and _acme-challenge to add as well.