Add instance admin as here described. Consider that you must add the port which is logged in the beginning of the Zitadel Pod.
List instances and get the instance ID in the response: API-Docs
curl --request POST \\
--url <https://zitadel.domain.com/system/v1/instances/_search> \\
--header 'Authorization: Bearer ey123.asdf.asdf' \\
--header 'Content-Type: application/json'
Add new domain: API-Docs
curl --request POST \\
--url <https://zitadel.makefermion.com/system/v1/instances/><instance-ID>/domains \\
--header 'Authorization: Bearer ey123.asdf.asdf' \\
--header 'Content-Type: application/json' \\
--data '{
"domain": "account.new-domain.app"
}