unfortunately no conflict, before the system did not send emails we can confirm
of not having updated,
that you have not run or installed any other plugin or application
that you have not touched any files or settings
I think the problem is woocommerce, because the email sending test says: Could not instantiate mail function.
We solved the problem tonight, we are using an external “Mailjet” service which solved the whole problem.
I believe that the technicians will have to investigate why this problem also happens to other users of woocomemrce after some time and without a real reason