Add Calendar Event using REST API

Development
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3 
    const url = DISCOURSE_BASE_URL + '/posts.json';
    const message = {
        method: 'POST',
        headers: {
            'Api-Key': DISCOURSE_API_KEY,
            'Api-Username': DISCOURSE_API_USERNAME,
            'Content-Type': 'application/json'
        },
        body: JSON.stringify({
            "title": title, 
            "raw": content,
            "category": categoryId
        })
    };
    const response1 = await fetch(url, message);

I get “Unprocessable Entity” when raw as follow:

[event start="2024-05-16 19:00" status="public" name="585" timezone="Europe/Paris" allowedGroups="trust_level_0" end="2024-05-16 21:00"]
[/event]

When i get off event declaration and put alternative description, my forum gets updated but as soon as i put event declaration, i get Unprocessable Entity.

I don’t understand what i’m doing wrong.