If you have forgotten the administrator user name, you can find it by inspecting the as-install/domains/domain-name/config/admin-keyfile file, where domain-name is the name of the domain. In the default domain, domain1, the file to inspect is as-install/domains/domain1/config/admin-keyfile. For a different domain, substitute its name in the path.

If you have forgotten the administrator password, one solution is to create a new domain with the admin username and password that you want, then copy the entry from the config/admin-keyfile file in that new domain to the other domain.