Grails Web Service - JSON endpoint working locally but not when deployed

I was using the Grails documentation to create a JSON endpoint out of one my domain classes. I'm perplexed because it works locally, but when deployed to my production environment (AWS Elastic Beanstalk), hitting the endpoint results in a 404. Here is how I defined the endpoint using the @Resource annotation:

@Resource(uri='/fbusers', formats=['json'])
class FacebookUser {

    Long uid
    String accessToken
    Date accessTokenExpires

    // Added fields
    String username 
    String profilePictureUrl 

    static belongsTo = [user: User]

    static constraints = {
        uid unique: true
    }
}

Works locally: http://localhost:8080/myapp/fbusers

Returns 404 in prod: mydomain.org/fbusers

Has anyone seen anything like this?