Problems getting gptel to talk to Mistral Le Chat

[mok0]

Briefly describe what you are trying to do

I have been trying to get gptel to work the Mistral Le Chat on the remote model. I have created a login, and fetched an api. I have verified that I am allowed to use the mistral-small model (but not the large one). I even asked Le Chat to help me get it right, but it seems she is just as confused as I am. We finally ended up with this configuration:

(setq gptel-backend
      (gptel-make-openai "MistralLeChat"
                         :host "https://api.mistral.ai/v1"
                         :protocol "https"
                         :key (get-mistral-api-key)
                         :models '("mistral-small")))

but I get the response:

MistralLeChat error: (((4c09fc6eba4df2cf668708e3dc5faa0b . 0)) Could not parse HTTP response.) Could not parse HTTP response.

Le Chat says it's API is OpenAI compatible, so I suppose using the gptel-make-openai macro should work. She and I tried many times but I don't think she knows. Is there a human here that can help?

Additional context
Emacs version: 29.4
Operating system: Linux 6.11.9