domainName

Fully qualified domain name (FQDN), such as www.example.com, that you want to secure with an ACM certificate. Use an asterisk (*) to create a wildcard certificate that protects several sites in the same domain. For example, *.example.com protects www.example.com, site.example.com, and images.example.com.

In compliance with RFC 5280, the length of the domain name (technically, the Common Name) that you provide cannot exceed 64 octets (characters), including periods. To add a longer domain name, specify it in the Subject Alternative Name field, which supports names up to 253 octets in length.