Standalone function is not working

Standalone function is not working

Hi,
We have created a standalone function to integrate with a third-party service using OAuth. However, the standalone function's REST API key is expiring automatically after some time. When we regenerate the API key from the admin account, the function starts working fine again.

Is there any specific reason why the API key is expiring automatically? How can we ensure that the API key remains valid or resolve this issue?