Bring your own domain:
You must provide a domain name in the "hostname" field. This will be your Mastodon server domain. You may register a domain here.
If you have a website on example.com then your Mastodon installation cannot use that domain.
But you can use a example.com subdomain (examples: social.example.com, mastodon.example.com or anythingelse.example.com)
10% of profit from this service will be donated to Mastodon gGmbH. and o3o.foundation