Even if import ldif schema created with ADS Schema editor succeeded. The restart of the server failed. Having a look on the ldif stored by the server, it seems the attribute is B64 break the start of the server with the message:
[21:00:30] ERROR [org.apache.directory.server.UberjarMain] - Failed to start the service.
org.apache.directory.api.ldap.model.exception.LdapInvalidAttributeValueException: ERR_13215_VALUE_EXPECT_STRING The value is expected to be a String
The property is:
make the start of the possible.