Most likely in your case

Then open Elementor again.

3. Update Elementor and Elementor Pro together

Your earlier errors came from:

elementor-pro/plugin.php
elementor/core/experiments/manager.php

That makes an Elementor/Elementor Pro compatibility problem worth checking. Make sure both plugins are updated together to compatible versions, rather than running an older Pro against a newer Elementor (or vice versa).

4. Regenerate Elementor files

In WordPress go to:

Elementor → Tools

Then run the available options for:

Regenerate CSS & Data

and clear Elementor/cache data if your version exposes those options.

Then clear your WordPress/server/CDN cache.

5. Check the actual failed JSON request

Open Chrome:

F12 → Network

Then open Elementor and reproduce the error.

Look for a request shown in red, especially requests containing:

wp-json
admin-ajax.php
elementor

Click it and open Response.

If the response starts with something like:

<br />
<b>Fatal error</b>

or:

Deprecated:

or:

Warning:

then that PHP output is the reason JSON parsing fails.

If it returns:

500 Internal Server Error

then there is a server/PHP/plugin fatal error behind it.

6. Check `debug.log`

After reproducing the Elementor error once, open:

wp-content/debug.log

Go to the very bottom.

You are looking for:

PHP Fatal error:

Uncaught Error:

Uncaught TypeError:

Parse error:

The two Deprecated messages you previously pasted are not enough to identify the crash.

7. Test the WordPress REST API

While logged out or in another tab, open:

https://dreamiptv.fr/wp-json/

A working REST API should return JSON, not a WordPress HTML page. WordPress documents that the REST API uses JSON for its responses.

If /wp-json/ itself gives an error, HTML, redirect loop, or 500 response, Elementor will have trouble with requests that depend on the API.