i looked at the promptflow source code repo, seems like the connection type 'OpenAI' is not passed down from the callers for some reason. sorry that i dont have openai setup to debug.

if you have the local code, might step in or setup a debug point at below file, line 129. then try to work out which part of the code failed to set connection_type.

https://github.com/Azure-Samples/ai-rag-chat-evaluator/blob/main/src/evaltools/eval/evaluate.py#L172

https://github.com/microsoft/promptflow/blob/main/src/promptflow-core/promptflow/core/_prompty_utils.py

https://github.com/Azure/azure-sdk-for-python/blob/main/sdk/evaluation/azure-ai-evaluation/azure/ai/evaluation/_evaluators/_common/_base_prompty_eval.py#L83