Please note that XOData online (Preview) will no longer allow exploration of Test APIs. Info added on 12-Jan-2016 : Private/Testing API Requests will either be rejected with [405: Method not allowed] or status [Test Service: Not Allowed] will be set in OData Directory. Please check OData Directory as there might already be a public/demo version of API in the directory that is allowed.
This online-preview version of XOData is only for exploring OData APIs that are publicly open and accessible. By using any OData API for exploration on this website, you are confirming it as a public API hence it can be added to Open OData Directory for general access.
Please note that XOData Chrome App is required to access private OData APIs that need user/password.