RAG not working with Anthropic Key and JS-SDK

Hi!

I tried to leverage the full RAG-functionality of weaviate-cloud. I could not get any results with the JS-SDK, using my anthropic API-key in the respective header. Instead I received the following Error:

WeaviateQueryError: Query call with protocol gRPC failed with message: /weaviate.v1.Weaviate/Search UNKNOWN: explorer: get class: concurrentTargetVectorSearch): explorer: get class: extend: extend generate: client not found, empty provider
    at <anonymous> (/xxx/node_modules/.pnpm/weaviate-client@3.4.0_encoding@0.1.13/node_modules/weaviate-client/dist/node/esm/grpc/searcher.js:46:19)
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)

Apart from that I could easily perform embeddings and hybrid search, so RAG seems the culprit here. I tried both, the REST and the grpc Endpoint, because the documentation does not clarify which one to use. Using the grpc endpoint resulted in this error:

WeaviateStartUpError: Weaviate startup failed with message: Weaviate failed to startup with message: The request to Weaviate failed with status code: 415 and message:
    at <anonymous> (/xxx/node_modules/.pnpm/weaviate-client@3.4.0_encoding@0.1.13/node_modules/weaviate-client/dist/node/esm/connection/helpers.js:52:11)

Can somebody tell me what’s going on here?

Thank you!