get_headers(): SSL operation failed with code 1

That error occurs when you're trying to access a URL without a valid SSL certificate. You can work around this by overriding the default stream context, which will affect all subsequent file operations (including remote URLs)

<?php
stream_context_set_default( [
    'ssl' => [
        'verify_peer' => false,
        'verify_peer_name' => false,
    ],
]);

print_r(get_headers('https://200.35.78.130/'));

Alternatively, if you're using PHP 7.1+, you can create a temporary context using stream_context_create and pass it directly to the function, to avoid overriding the default:

$context = stream_context_create( [
    'ssl' => [
        'verify_peer' => false,
        'verify_peer_name' => false,
    ],
]);

print_r(get_headers('https://200.35.78.130/', 0, $context));

Thanks to Matthijs Wessels in the comments for pointing it out.