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## Common errors

### 404 - ContentNotFound when trying to get content with Content Delivery 

  • **Do you enable MultiSiteFilteringEnabled option?** If enabled, Optimizely Content Delivery API returns only the contents of the current site based on the request context.

  • **Do you use the correct Accept-Language header?** Content Delivery API returns content based on the language passed in the Accept-Language header. Use the Accept-Language header to specify the locale variant of content that the client prefers (see [Mozilla - MDN Web Docs](🔗) for more information).

    The problem is some browsers, such as Chrome, automatically add its preferred language to the Accept-Language header, if the header value is not manually set by the user. In this case, the client should manually pass the Accept-Language header to prevent the browser from adding its own header value.

    If you are using the Content Delivery API in an AJAX application, you can specify/override the Accept-Language header value in your front-end code. See this external [blog post](🔗) for a code sample.

### 404 Http Error when sending request to Content Delivery endpoints

  • **Have you registered Content Delivery API services? ** To enable Content Delivery API endpoints, you need to call this line in your \_Startup \_file:



### 404 Http Error when sending a request to token endpoints in EPiServer.OpenIDConnect

Make sure you have added the following lines at the bottom in _Startup.cs_ file (see [API authentication](🔗).



### I cannot get my images from my content

Use a property model converter (`IPropertyModelConverter`) which lets you customize the output sent to the Content Delivery API. See an example in the [Music Festival](🔗) project. See also [Serialization](🔗) and How to [customize data returned to clients](🔗).