Hi @TeamEquipe,
This looks like the data is corrupted, the page is not recognizable, it will load but processing will fail. Would you mind providing your FTP login credentials as well? There are multiple errors and I may able to find from debug files.
For the meantime, you could try testing for a plugin conflict. You can do this by deactivating all third party plugins, and seeing if the problem remains. If it’s fixed, you’ll know a plugin caused the problem, and you can narrow down which one by reactivating them one at a time.
Or re-create the same page (generating new valid data).
Let us know how it goes!