if strings.Contains(err.Error(), "User DN not found for") {
				return "", nil
			}
			return "", fmt.Errorf("Unable to find user DN: %w", err)
		}
		return bindDN, nil
	}

	// Since the username parses as a valid DN, check that it exists and is
	// under a configured base DN in the LDAP directory.
	validDN, isUnderBaseDN, err := l.GetValidatedUserDN(conn, username)
	if err == nil && !isUnderBaseDN {