Acme::Client::Error::RejectedIdentifier: Error creating new order :: Cannot issue for "test": Domain name needs at least one dot // Where can I find the table in database to search for the project where this domain is used

Within sidekiq I receive this error:

Acme::Client::Error::RejectedIdentifier: Error creating new order :: Cannot issue for "test": Domain name needs at least one dot

The reason is that someone in one project has probably tried to create a custom domain for pages, but has not entered a valid domain name. Getting a certificate for this is tried every 10 minutes. How can I find out what project this is? I was not able to find where the custom domain name is stored in the DB, any hint? Unfortunately, there is no admin overview with custom domains configured or similar.