How do we get the suffix authorization?

I'm trying to create a collection with a collection name that has a full stop in it (e.g. My.NFT), when I click Create Collection and try to execute the action I get the error "assertion failure with message: When the collection name has a suffix, the suffix authorization is required". How do we get the suffix authorization? 

You have to have a WAX account with the name of the collection. That way, you can name your collection whatever the account‘s name is. But via the regular methods, you can’t get a suffix into the collection name.