Calling external APIs stopped working

Hi all
I have an external API issue

I was working on a GPT agent with actions destined to call external APIs.
It worked well until a week ago : at the end of April, it suddenly stopped working : The external API calls now return no response.

I tested the exact same prompt & actions on another account and it works fine; so the issue is linked to my GPT account.

Where should I look in order to fix this ?

Hope someone can help, thanks !

Ok. I started a new gpt agent with exactly the same instructions & actions and it worked. I don;t understand why, but at least the problem is solved.