Running Jenkins in ECS cannot get LDAP to work

Hello all, since moving our Jenkins to use ECS instead of EC2 we are unable to connect to LDAP. The security groups are set ok etc but just keep getting:

javax.naming.AuthenticationException: [LDAP: error code 49 - 80090308: LdapErr: DSID-0C090447, comment: AcceptSecurityContext error, data 52e, v3839]

the only change is that its moved to ecs - anyone else had issues around this?