fread() SSL forced connection interruption by remote host

[hgc2002]

Warning: fread(): SSL: Se ha forzado la interrupci¾n de una conexi¾n existente por el host remoto.
in C:\aaa\repositories\Stub_ML_Server\vendor\mpyw\php-hyper-builtin-server\socket\src\SecureConnection.php on line 36

In English is something like:

The interruption of an existing connection by the remote host has been forced.

This is my request:
curl -k https://localhost:8000/ping

I only get the error message when I break curl command manually (because it never ends !!!)

I've started the server as:
php vendor/mpyw/php-hyper-builtin-server/hyper-run -s localhost:8000 -n 1 -r router.php

(router.php is the same I use with the PHP builtin server, and "/ping" request is well handled by it)

Any idea?

[mpyw]

Sounds like Connection reset by peer error