Vertex AI Vector Search - "UNIMPLEMENTED" Error with LlamaIndex

[Montassar_Jazir]

I'm using LlamaIndex with a vector store index to retrieve context, but I get the following error when calling findNeighbors:

{"error":{"code":404,"message":"Could not resolve /v1beta1/projects/xxx/locations/europe-west6/indexEndpoints/xxx:findNeighbors to a method.","status":"UNIMPLEMENTED"}}

It seems like the method is not recognized.

Here’s the LlamaIndex documentation I’m referencing:

https://docs.llamaindex.ai/en/stable/examples/vector_stores/VertexAIVectorSearchDemo/ 

Would appreciate any insights!