You should be able to debug further by trying a raw connection.
$ openssl s_client -connect irc.chat.twitch.tv:6697 -quiet
and try inputting
PASS whatever
NICK justinfan123
and see if you get in. This will let you know if it’s something between the servers themselves, or an issue with your code.
What you should see in the console is this:
$ openssl s_client -connect irc.chat.twitch.tv:6697 -quiet
depth=2 C = US, O = DigiCert Inc, OU = www.digicert.com, CN = DigiCert Global Root CA
verify return:1
depth=1 C = US, O = DigiCert Inc, CN = DigiCert SHA2 Secure Server CA
verify return:1
depth=0 C = US, ST = California, L = San Francisco, O = "Twitch Interactive, Inc.", CN = *.chat.twitch.tv
verify return:1
PASS whatever
NICK justinfan123
:tmi.twitch.tv 001 justinfan123 :Welcome, GLHF!
:tmi.twitch.tv 002 justinfan123 :Your host is tmi.twitch.tv
:tmi.twitch.tv 003 justinfan123 :This server is rather new
:tmi.twitch.tv 004 justinfan123 :-
:tmi.twitch.tv 375 justinfan123 :-
:tmi.twitch.tv 372 justinfan123 :You are in a maze of twisty passages, all alike.
:tmi.twitch.tv 376 justinfan123 :>