DocumentDB / CosmosDB - Entity with the specified id does not exist in the system
I just spent a couple of hours troubleshooting this, only to find that I had firewalled my instance to a point where I could not connect locally. Keep in mind that the Azure portal document query will obviously still work even when you have no direct access via the API / C# client.
Try setting the firewall to allow All Networks temporarily to check access.
I would check in the portal that the "GetMemberbyId" is the name of the stored procedure for the collection you are trying to run it on. Could be the stored procedure is on a different collection or that the stored procedure is named something else.
If that all checks out.. I have had more luck with the __.filter() way of querying documents on the server. See:http://azure.github.io/azure-documentdb-js-server/