The recommended use of mongoldap is to provide it a mongod config file to test a connection.
Right now all config options except ldap specific ones terminates the tool with the error: "Unrecognized option"
The work-around is to create a config file using only ldap options or use the command line parameters instead.
Additionally it would be desirable to support setting/validating the choice of authentication mechanism PLAIN:
--setParameter authenticationMechanisms=PLAIN
setParameter: authenticationMechanisms: PLAIN