When using an external authentication mechanism like LDAP, the
sonar.security.localUsers property must be set in $SONARQUBE_HOME/conf/sonar.properties to the list of all the technical accounts (comma-separated list). These accounts will not be authenticated against LDAP but against the SonarQube engine. On the opposite, all the accounts that are not flagged as local will only be authenticated against LDAP. By default
admin is a technical account.
sonar.jdbc.schema is property deprecated
Read Installing to configure SonarQube without using this property.