---
title: "501_BadRequest_MethodNotImplemented"
description: "501_BadRequest_MethodNotImplemented"
keywords: "501 BadRequest_MethodNotImplemented Business Central Error bound action"
url: "https://myrapidi.com/wiki/501_badrequest_methodnotimplemented"
locale: "en"
published: "2024-04-18T15:08:03Z"
modified: "2025-03-07T20:42:22Z"
---

 The following message **Status code received: 501 Not Implemented Response body: {"error":{"code":"BadRequest\_MethodNotImplemented","message":"The OData filter expression is not supported. CorrelationId: 35e16c80-fa86-41a1-a0fc-c91c510276ab."}}** indicates that the request made to the OData service was not successfully processed because the filter expression used in the query is not supported.   
  

**Possible Causes:**  
  

1. **Unsupported Filter Operator** – Some complex filters (like startswith(), endswith(), or nested conditions) may not be allowed.
2. **Query Not Allowed on That Endpoint** – The API might not support filtering on the field you specified.
3. **OData Version Compatibility Issue** – The API might be expecting a different OData version where certain filters are restricted.

**Possible Solutions:**  
  

1. Check the API documentation to see which filter expressions are supported.
2. Simplify or modify the filter expression to a more basic format.