Server response header is not getting cleared

[somnathpawar]

I want to clear the server information from the Nginx response header "Server". I tried following things:
more_set_headers 'Server: my-server';
more_clear_headers 'Server';

But somehow, it is not hiding a Server header and showing nginx/1.14.0 (Ubuntu) as full details on the server. Any idea?

The header works fine for clearing other headers such as "Content-Type" or "Content-encoding" but not working for "Server" header.

Thanks in advance!