Couldn't retrieve http://professorvn.net, and the only explanation I have is:

500 Can't connect to professorvn.net:443 Content-Type: text/plain Client-Date: Wed, 15 Jan 2025 08:28:27 GMT Client-Warning: Internal response Can't connect to professorvn.net:443 LWP::Protocol::https::Socket: SSL connect attempt failed with unknown error error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol at /usr/local/lib/perl5/site_perl/5.8.8/LWP/Protocol/http.pm line 49.