Hi Fredrik,

The CustomContentApiRoutingEventHandler is not part of the given namespaces or EPiServer.ContentDeliveryApi. You have to create a class and need to write your logic like below:

    /// <summary>
    /// Custom routing event handler for Music Festival.    
    /// </summary>
    public class CustomContentApiRoutingEventHandler : RoutingEventHandler
    {
        public CustomContentApiRoutingEventHandler(
            IContentRouteEvents routeEvents,
            ServiceAccessor<HttpContextBase> httpContextAccessor,
            ContentApiRouteService contentApiRouteService)
            : base(routeEvents, httpContextAccessor, contentApiRouteService)
        {            
        }

        // If language does not exists in the routing context, we return ContentLanguage.PreferredCulture as default language
        protected override string GetLanguage(SegmentContext routingContext, HttpRequestBase request)
        {
            var language = routingContext.Language ?? routingContext.ContentLanguage ?? ContentLanguage.PreferredCulture.Name;
            
            return language;
        }       
    }

Thank you, I will try and see if this will help.