Domain name. Must be 4-255 characters in total, and each dot-separated label must be no more than 48 characters (labels consist of letters, digits and inline hyphens, not starting or ending with a hyphen). Must contain at least one dot; must not contain the substring sendcloud; sub-domain count per main domain is limited (max 10). Only a single domain is accepted — a semicolon-separated multi-name value returns 41013.