GPTs doesn't respond 100% of the time?

I have created a GPTs whose role is to generate blog posts from sources that are saved on a website hosted on one of my servers. The GPTs works 70% of the time but sometimes it tells me “I can’t proceed as requested” when I’d like it to generate an article.

The steps of my GPTs are quite simple:
1 - it connects to my website and retrieves the data, which is in JSON format for easier processing
2 - It asks the user to select a source among those retrieved to generate an original article
3 - Once the user has validated the article, GPTs generates an image that captures the main idea of the article with DALL-E and generates a Linkedin post.

Additional information: I ask my GPTs to return the answer in a Markdown code block, but sometimes it ignores this directive and displays the text “normally”.

Do you have any idea why GPTs doesn’t respond 100% of the time?

Have a nice day.