Remote ping doesn't work for me

I configured remote ping using POST request to my remote server and it doesn't work for me.

There are no pings in the history (!?). and no request received on remote server.
I have tested it with simple script:

file_put_contents('/tmp/result1.txt', var_export($_POST, true));

I have tested POST request from other WP plugins to the same server and it works fine.
Could you please help. Do I need