Logprobs return None for meta-llama/llama-3.1-70b-instruct:free？

[yanglebupt]

Describe the bug
Logprobs return None for meta-llama/llama-3.1-70b-instruct:free

To Reproduce
completion = self.client.chat.completions.create(
model="meta-llama/llama-3.1-70b-instruct:free",
messages= [
{"role": "system", "content": self.prompt_system},
{"role": "user", "content": example["text"]}
],
max_tokens=1,
temperature=0,
logprobs=True,
top_logprobs=5
)
print(completion.choices[0].logprobs) # print None?

Expected behavior
I want return Logprobs