Failed to load resource: the server responded with a status of 500 ()

Hello,
My form’s submit button is not working. I can fill out the form but it is not getting submitted. When I press Submit, it checks if there are any errors in the fields. If there are no errors, try to submit but I get infinite spinning. When reviewing in the browser console I see the following error.

Failed to load resource: the server responded with a status of 500 ();

Clicking on the link shows the following information:

{“code”:”rest_no_route”,”message”:”No route was found matching the URL and request method.”,”data”:{“status”:404}}

CF7 is already up-to-date.

What is the solution, what do I do?

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